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    Wyświetlanie 1-42 z 42
    Tytuł:
    Analysis of Secondary Interactions and Structure-Activity-Relationship of Two Benzoic Acids
    Autorzy:
    Dinesh, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1400141.pdf
    Data publikacji:
    2013-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    Opis:
    Two benzoic acids, 2-[3-(o-methylphenoxymethyl)-5-phenyl-[1,2,4]triazol-4-yl]-benzoic acid [I] and 2-[3-(m-methylphenoxymethyl)-5-phenyl-[1,2,4]triazol-4-yl]-benzoic acid [II] were synthesized and their crystal structures have been analyzed to the reliability factor of 4.2% [I] and 4.8% [II]. Different structural motifs (i.e. chains, dimmers, rings, etc.) bonded through C-H...π, ı...ı and hydrogen interactions have been analyzed. Structure-activity-predictions have been identified on the basis of structural fragments and variation in activities has been observed in both the compounds. The detailed analysis of non-covalent interactions illustrates that the shifting of methyl group from ortho-to-para increases the bioactivity-predictions of "Endothelin B receptor antagonist".
    Źródło:
    Acta Physica Polonica A; 2013, 123, 4; 704-708
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interaction of the Components in the $BaO-Tb_2 O_{3+δ}-CuO$ and Related Systems
    Autorzy:
    Zaremba, O.
    Gladyshevskii, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398239.pdf
    Data publikacji:
    2018-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    Opis:
    The isothermal section of the phase diagram of the $BaO-Tb_2 O_{3+δ}-CuO$ system at 1173 K was constructed based on X-ray powder diffraction data. The existence of the compounds BaTbO₃ (SrZrO₃ structure type, I4/mcm, a = 0.6034(1), c = 0.8576(1) nm) and Ba₄₄Cu₄₅O₉₀ (own structure type, Im-3m, a =1.8266(3) nm) was confirmed in the binary BaO-Tb₂O₃ and BaO-CuO systems, respectively, but no ternary oxides were found. The investigation of samples with nominal composition $A_{0.5}Tb_{0.5}TO_3$ (A = Ca, Sr or Ba, T = Ni or Zn) showed the presence of phases from the corresponding binary systems, or unreacted reagents.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 4; 1024-1026
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Crystalline Structure of Potassium Holmium Double Tungstate
    Autorzy:
    Borowiec, M.
    Dyakonov, V.
    Woźniak, K.
    Dobrzycki, Ł.
    Majchrowski, A.
    Michalski, E.
    Zubov, E.
    Khatsko, E.
    Zayarnyuk, T.
    Szewczyk, A.
    Gutowska, M.
    Rykova, A.
    Barański, M.
    Domukhovski, V.
    Shtyrkhunova, V.
    Iwanowski, P.
    Żmija, J.
    Szymczak, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1505085.pdf
    Data publikacji:
    2011-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    Opis:
    The potassium holmium double tungstate was prepared by using top seeded solution growth technique. Structural investigations have been performed at room temperature. The $KHo(WO_4)_2$ single crystal belongs to the monoclinic space group C2/c with the unit-cell parameters: a = 10.624(2) Å, b = 10.352(2) Å, c = 7.5434(15) Å, β = $130.78(3)^{o}$, and Z = 4. The atomic coordinates, isotropic and anisotropic displacement parameters and interionic distances for the studied structure were determined.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 6; 835-837
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Refinement of the Modulated Structures of Pb-Free and Pb-Doped Bi-2223 HTSC
    Autorzy:
    Shcherban, O.
    Akselrud, L.
    Giannini, E.
    Gladyshevskii, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1030916.pdf
    Data publikacji:
    2018-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    74.72.-h
    Opis:
    The incommensurate modulated structures of Pb-free and Pb-doped Bi-2223 phases were refined on single-crystal X-ray diffraction data.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 4; 1027-1029
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural Study of (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ in the Low-Temperature Phase
    Autorzy:
    Fukami, T.
    Higa, N.
    Chen, R. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/2013261.pdf
    Data publikacji:
    2000-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    64.60.Fr
    Opis:
    The crystal structure of tetraammonium dihydrogen triselenate, (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$, in the low-temperature phase at 141 K is studied by X-ray diffraction. The space group symmetry (triclinic P1) and the structure parameters are determined. By the shift of the Se atom from the center of the SeO$\text{}_{4}$ tetrahedron, it is suggested that the (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$ (SeO$\text{}_{4}$)$\text{}_{3}$ crystal in the low-temperature phase is ferroelectric with the electric dipole moment along the c-axis. The rotation of the SeO$\text{}_{4}$ tetrahedron suggested by electron paramagnetic resonance measurements is discussed.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 4; 663-670
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    X-Ray Study of Synthetic Alunite
    Autorzy:
    Paszkowicz, W.
    Dynowska, E.
    Świerkocki, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931684.pdf
    Data publikacji:
    1994-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.10.Lx
    61.66.Fn
    Opis:
    Synthetic alunite was obtained by two different synthesis methods. Powder data obtained with a standard Bragg-Brentano geometry of two analyzed samples are reported for a broad angular range. The chemical analysis as well as the unit-cell dimensions indicate that the analyzed alunite is K and Al deficient and contains excess water. A need for high resolution diffraction experiments is expressed.
    Źródło:
    Acta Physica Polonica A; 1994, 86, 4; 621-627
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Crystal Structure of K$\text{}_{3}$Na(SeO$\text{}_{4}$)$\text{}_{2}$ at 340 K
    Autorzy:
    Fukami, T.
    Chen, R. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1993089.pdf
    Data publikacji:
    1998-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    64.60.Fr
    Opis:
    The crystal structure of tripotassium sodium diselenate, K$\text{}_{3}$Na(SeO$\text{}_{4}$)$\text{}_{2}$, at 340 K is studied by single-crystal X-ray diffraction. The space group symmetry (trigonal P3̅) and structure parameters are determined. It is found that there exists the difference of the direction and the magnitude of the atomic displacement at the two phase transitions of 346 K and 334 K.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 5-6; 795-801
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure Refinement of the Semiconducting Compound $Cu_3TaS_4$ from X-Ray Powder Diffraction Data
    Autorzy:
    Delgado, G.
    Contreras, J.
    Mora, A.
    Durán, S.
    Muñoz, M.
    Grima-Gallardo, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1493612.pdf
    Data publikacji:
    2011-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.50.Nw
    61.66.Fn
    Opis:
    The ternary compound $Cu_{3}TaS_{4}$ has been investigated by means of X-ray powder diffraction and its structure has been refined by the Rietveld method. This compound is isostructural with the sulvanite mineral $Cu_{3}VS_{4}$, and crystallizes in the cubic $P \bar{4} 3m$ space group (No. 215), Z = 1, with unit cell parameters a = 5.5145(1) Å and V = 167.70(1) $Å^{3}$. The refinement of 14 instrumental and structural parameters converged to $R_{p}$ = 4.4%, $R_{wp}$ = 6.8%, $R_{exp}$ = 5.5% and S = 1.2 for 4501 step intensities and 33 independent reflections.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 3; 468-472
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis, Structure, and Magnetism of Heterobinuclear Complex GdCu(OTf)$\text{}_{3}$(bdmap)$\text{}_{2}$(H$\text{}_{2}$O)·THF
    Autorzy:
    Gao, Song
    Borgmeier, O.
    Lueken, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945652.pdf
    Data publikacji:
    1996-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    36.40.+d
    61.66.Fn
    Opis:
    A new heterobinuclear Gd(III)-Cu(II) complex [GdCu] = GdCu(OTf)$\text{}_{3}$(bdmap)$\text{}_{2}$(H$\text{}_{2}$O). THF (OTf=SO$\text{}_{3}$CF$\text{}_{3}$) has been prepared by reaction of 1,3-bis(dimethylamino)-2-propanol (bdmapH) with Cu(OCH$\text{}_{3}$)$\text{}_{2}$ and lanthanide triflate salt Gd(OTf)$\text{}_{3}$ in a 2:1:1 ratio in THF. Its structure has been determined by single-crystal X-ray diffraction. [GdCu] crystallizes on an orthorhombic lattice, space group P2$\text{}_{1}$2$\text{}_{1}$2$\text{}_{1}$ with Z=4 and a=11.023(3) Å, b=17.555(15) Å, c=20.212(7) Å, V=3911(4) Å$\text{}^{3}$. For 2194 independent reflections with I > 1σ(I), full-matrix least squares refinement with anisotropic thermal parameters for Gd, Cu, S, and O converged to unweighted and weighted R factors of 0.074 and 0.085, respectively. Gd is coordinated by six O and two N. Cu is coordinated by two O and two N. Gd and Cu are bridged by two alkoxo O atoms with separation of 3.311(4) Å. The magnetic susceptibilities were measured over the temperature range 1.7-20 K at the field range 0.01-0.5 T. The data of [GdCu] at 0.05 T have been analyzed with the use of a Heisenberg spin Hamiltonian Ĥ=-2JŜ$\text{}_{Gd}$·Ŝ$\text{}_{Cu}$ giving g=2.046(2), J=-0.039(3) cm$\text{}^{-1}$. This shows that Gd-Cu spins are coupled very weakly in the antiferromagnetic manner, though the distance between Gd(III) and Cu(II) ions is rather short.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 2; 393-398
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and Structure Characterisation of Micro-and Nanocrystalline Powders of Dy_{1-x}R_xFeO₃ (R = La, Pr, Nd, Sm, Gd)
    Autorzy:
    Pavlovska, O.
    Lutsyuk, I.
    Kondyr, A.
    Zhydachevskyy, Ya.
    Vakhula, Ya.
    Pieniążek, A.
    Vasylechko, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1029717.pdf
    Data publikacji:
    2018-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    61.05.cp
    Opis:
    This work deals with the study of the phase and crystal structure behaviour of new micro- and nanocrystalline ferrites Dy_{1-x}R_xFeO₃ obtained by solid state reactions (R = La, Pr) and sol-gel citrate (R = Nd, Sm, Gd) techniques. It was established that all synthesized samples adopt orthorhombic perovskite structure isotypic with GdFeO₃. Unit cell dimensions and atomic coordinates of the mixed rare earth ferrites derived by full profile Rietveld refinement technique agree well with the data of the "pure" DyFeO₃ and RFeO₃ compounds, thus proving formation of continuous solid solutions Dy_{1-x}R_xFeO₃ in the DyFeO₃-RFeO₃ systems (R = La, Pr, Nd, Sm, Gd). Peculiarity of the Dy_{1-x}La_xFeO₃ series is the lattice parameters crossover and formation of dimensionally tetragonal structure at x ≈0.97.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 4; 802-805
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural Phase Transition and Crystal Structure for (ND$\text{}_{4}$)$\text{}_{4}$D$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ at Low Temperature
    Autorzy:
    Fukami, T.
    Chen, R. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/2027434.pdf
    Data publikacji:
    2001-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    64.60.Fr
    Opis:
    Differential scanning calorimetry and X-ray diffraction measurements were performed on a deuterated tetraammonium dihydrogen triselenate (ND$\text{}_{4}$)$\text{}_{4}$D$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ crystal at low temperatures. A structural phase transition is found at 182.0(3) K. The space group symmetry (triclinic P1) and the structure parameters are determined at 145 K in the low-temperature phase. The isotope effect for an asymmetric O-H-O hydrogen bond by the substitution of deuterium is discussed.
    Źródło:
    Acta Physica Polonica A; 2001, 100, 1; 53-65
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Growth by LHPG, Structure and Spectroscopy of Nd$\text{}^{3+}$-Doped Ba$\text{}_{2}$NaNb$\text{}_{5}$O$\text{}_{15}$ Nonlinear Single-Crystal Fibres
    Autorzy:
    Foulon, G.
    Ferriol, M.
    Brenier, A.
    Cohen-Adad, M. T.
    Boulon, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945469.pdf
    Data publikacji:
    1996-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    78.20.-e
    Opis:
    The renewal of the second order nonlinear crystals is very strong in laser materials optics. We are involved in the search for new systems based upon highly nonlinear niobate crystal family. Among these crystals, Ba$\text{}_{2}$NaNb$\text{}_{5}$O$\text{}_{15}$ is characterized by the highest nonlinear parameters but, unfortunately, it is difficult to grow crackless samples. The obtention of good quality and crackless Ba$\text{}_{2}$NaNb$\text{}_{5}$O$\text{}_{15}$ single crystals doped with different concentrations of Nd$\text{}_{2}$O$\text{}_{3}$ is reported. The crystals were grown as monocrystalline fibres by the laser heated pedestal growth technique. A new determination of the crystallographic structure of Ba$\text{}_{2}$NaNb$\text{}_{5}$O$\text{}_{15}$ has been performed. The structure of fibres doped with 1 at.% Nd$\text{}^{3+}$ was found orthorhombic with the new space group Pba2 instead of Cmm2. The well-known twinning of Ba$\text{}_{2}$NaNb$\text{}_{5}$O$\text{}_{15}$ due to the exchange of the a and b axes of the unit cell, which disturbs the optical properties, decreases as the Nd$\text{}^{3+}$ content of the fibre increases. Above 3%Nd$\text{}^{3+}$ ions, such monocrystalline fibres were found to be of tetragonal structure. Low temperature spectroscopy reveals that Nd$\text{}^{3+}$ ions substitute probably both Ba$\text{}^{2+}$ and Na$\text{}^{+}$ ions. The stimulated emission cross-section near 1060 nm of the $\text{}^{4}$F $\text{}_{3}\text{}_{/}\text{}_{2}$ → $\text{}^{4}$I$\text{}_{11}\text{}_{/}\text{}_{2}$ channel and its branching ratios are determined with the help of Judd-Ofelt analysis. This work shows that b-axis grown monocrystalline fibres are potentially self-doubling laser materials.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 1; 63-72
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cobalt Additives Influence on Phase Composition and Defect Structure of Manganese Dioxide Prepared from Fluorine Containing Electrolytes
    Autorzy:
    Sokolsky, G.
    Ivanov, S.
    Ivanova, N.
    Boldurev, Ye.
    Kobulinskaya, O.
    Demchenko, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1550089.pdf
    Data publikacji:
    2010-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    61.72.-y
    85.40.Ry
    Opis:
    Manganese dioxide samples were prepared from fluorine containing electrolytes with additives of $Co^{2+}$ ions. Atomic absorption spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis were the methods of the samples characterisation. Manganese dioxide at the presence of cobalt forms nanosized ramsdellite structure crystallites of mostly needle-like morphology with significant content of hydroxide groups. The main phase state in manganese dioxide samples obtained at the presence of cobalt is $γ-MnO_{2}$ with ramsdellite structure and low content of intergrowth defects. The sample doped both with lithium and cobalt can be indexed to a hollandite-type structure (tetragonal; space group I4/m) of $α-MnO_{2}$.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 1; 86-90
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Promising Synthetic Route Hydrothermal Synthesis of Non-Stoichiometric Cerium and Boron Containing Compounds and Characterization
    Autorzy:
    Çelik, G.
    Kurtuluş, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1181838.pdf
    Data publikacji:
    2014-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    82.33.Pt
    61.66.Fn
    61.05.cp
    Opis:
    Cerium, the most abundant rare earth element, and boron containing mineral (lithium tetraborate pentahydrate) were used for synthesizing rare earth borates. Alternatively, for preparing rare earth borates, hydrothermal technique can be used. The non-stoichiometric cerium and boron containing compounds were synthesized by hydrothermal method using cerium sulphate and lithium tetraborate pentahydrate in appropriate molar ratio. Characterizations were done by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray analysis, and thermogravimetric/differential thermal analysis.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 2; 325-326
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    ORR Electrocatalysis on Cr³⁺, Fe²⁺, Co²⁺-Doped Manganese(IV) Oxides
    Autorzy:
    Sokolsky, G.
    Zudina, L.
    Boldyrev, E.
    Miroshnikov, O.
    Gauk, N.
    Kiporenko, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1030872.pdf
    Data publikacji:
    2018-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    61.72.-y
    85.40.Ry
    Opis:
    The ionic dopant additives have different mechanisms of their influence upon MnO₂ electrocrystallisation process and depending on dopants added the following polymorphs are stabilised: α -MnO₂ (hollandite, I4/m) - NH₄⁺; γ -MnO₂ (ramsdellite, Pbnm) - Co²⁺, Fe²⁺; layered polymorph δ -MnO₂ (birnessite, C2/m) - Cr³⁺. The defect states of intergrowth method in ramsdellite matrix and twinning, OH groups studied by X-ray diffraction and the Fourier transform infrared mtehod, respectively, indicate their high content in case of Fe²⁺ and Co²⁺-doped manganese dioxide. CVA oxygen reduction reaction peaks were established after experiments in alkaline electrolytes and dioxygen (argon, air) atmosphere. Activity of doped samples studied is comparable with other published data. Both doped with Co²⁺ and Fe²⁺ samples display maximal currents and some distinctive features in oxygen reduction reaction.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 4; 1097-1102
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental and Theoretical Study of Zircon and Scheelite Phases of $DyVO_4$
    Autorzy:
    Ermakova, O.
    Paszkowicz, W.
    López-Solano, J.
    Muñoz, A.
    Dabkowska, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1431671.pdf
    Data publikacji:
    2012-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.70.Hj
    61.43.Bn
    61.66.Fn
    Opis:
    Polycrystalline zircon-type dysprosium orthovanadate, $DyVO_4,$ prepared from a single crystal grown by slow cooling from $PbO//PbF_2$ flux, was studied by X-ray diffraction. Rietveld refinement provided the following unit cell size and oxygen atom coordinates: a=7.14811(4) Å; c=6.30825(4) Å, V=322.323(3) Å3, y($O^{2-}$)=0.4300(4); z($O^{2-}$)=0.2082(4) which are of a particularly high accuracy and show consistency with earlier reported values. Density functional theory calculations within the generalized gradient approximation for the exchange-correlation energy were also performed, providing values of structure parameters which differ by less than 2% from the experimental ones. The agreement between theory and experiment demonstrates the value of these calculations for understanding the structure of compounds of $RVO_4$ family. In addition, density functional theory calculations were performed for the scheelite-type $DyVO_4$; also for this polymorph the discrepancy with the only known set of lattice parameters is less than 2%. Values of oxygen atom coordinates have not been reported yet for this polymorph; here, the calculated ones are quoted.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 4; 920-927
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Annealing on the Crystal Structure and Microstructure of Pr Doped $ZrO_{2}-Y_{2}O_{3}$ Nanocrystals
    Autorzy:
    Werner-Malento, E.
    Paszkowicz, W.
    Fidelus, J.
    Godlewski, M.
    Yatsunenko, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1550117.pdf
    Data publikacji:
    2010-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.46.-w
    61.66.Fn
    81.40.-z
    Opis:
    Rare-earth doped nanocrystalline yttria-stabilized zirconia (YSZ, $ZrO_{2}-Y_{2}O_{3}$) is, recently, a subject of studies because of its luminescent properties. The luminescence may be strongly influenced by the crystal structure and microstructure of the material. In this work, the X-ray diffraction study for Pr doped YSZ nanocrystals is presented. The phase composition dependence on the $Y_{2}O_{3}$ content and on heat treatment conditions is quantitatively determined using the Rietveld method and the similarities and differences between the present data for doped samples and earlier reported data for undoped material are discussed. A formation of high symmetry phases (cubic and tetragonal) is observed for high yttria content in agreement with general tendencies observed in literature for undoped samples.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 1; 91-97
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Crystal Structure and Magnetic Properties of Pyrrhotite-Type Compounds $Fe_{7-y}V_{y}S₈$
    Autorzy:
    Selezneva, N.
    Ibrahim, P.
    Toporova, N.
    Sherokalova, E.
    Baranov, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/1397027.pdf
    Data publikacji:
    2018-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    75.30.Kz
    75.50.Gg
    Opis:
    The pyrrhotite-type compounds $Fe_{7-y}V_{y}S₈$ have been synthesized and studied by means of the X-ray diffraction and magnetization measurements in order to reveal how the substitution of V for Fe affects the crystal structure, phase transition and magnetic properties. The growth of the V content in $Fe_{7-y}V_{y}S₈$ results in changes of the crystal structure and leads to a sharp decrease in the resultant magnetization, non-monotonous change of the coercive field and reduction of the magnetic ordering temperature. Unlike ferrimagnetic ordering in pyrrhotite Fe₇S₈ the compound V₇S₈ is observed to exhibit a Pauli-paramagnetic behaviour.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 3; 450-452
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analytic Equation of State and Thermodynamic Properties, for α-, β-, and γ-Si₃N₄ Based on Analytic Mean Field Approach
    Autorzy:
    Wang, L.
    Sun, J.
    Yang, W.
    Tian, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812044.pdf
    Data publikacji:
    2008-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    64.10.+h
    65.40.-b
    61.66.Fn
    Opis:
    The analytic mean field potential approach is applied to α-, β-, and γ-Si₃N₄. The analytic expressions for the Helmholtz free energy, internal energy, and equation of state were derived. The formalism for the case of the Morse potential is used in this work. Its six potential parameters are determined through fitting the compression experimental data of α-, β-, and γ-Si₃N₄. The calculated compression curves of α-, β-, and γ-Si₃N₄ are in good agreement with the available experimental data. This suggests that the analytic mean field potential approach is a very useful approach to study the thermodynamic properties of Si₃N₄. Furthermore, we predict the variation of the free energy and internal energy with the molar volume at several higher temperatures and calculate the temperature dependence of the molar volume, bulk modulus, thermal expansion coefficient and isochoric heat capacity at zero pressure.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 4; 807-818
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Combined X-Ray Diffraction and Absorption Study οf Crystalline Vanadium-Doped Lithium Disilicate
    Autorzy:
    Paszkowicz, W.
    Wolska, A.
    Klepka, M.
    abd el All, S.
    Ezz-Eldin, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1538928.pdf
    Data publikacji:
    2010-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.43.Fs
    61.66.Fn
    71.20.Ps
    81.05.Je
    Opis:
    Structure of vanadium-doped lithium disilicate, $Li_{2}Si_{2}O_{5}$ (Ccc2 space group) is studied. This crystalline phase is obtained by annealing of the doped lithium disilicate glass for 4 h at 550°C. X-ray diffraction and X-ray absorption near-edge structure analysis indicate location of vanadium atoms at Si sites. the lattice parameters are found to increase isotropically with increasing vanadium content. the valency of vanadium ions is discussed on the basis of X-ray absorption near-edge structure results.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 2; 315-318
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Simultaneous Doping of $Li^+$ and $Fe^{3+}$ Ions in the $LiMn_2O_4$ Spinel Structure
    Autorzy:
    Nowicki, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812247.pdf
    Data publikacji:
    2008-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    75.47.Lx
    68.18.Jk
    73.21.Cd
    Opis:
    A series of compounds $Li_xMn_{3-x-y}Fe_yO_4$ (x=1.0125;0≤y≤0.05) were synthesized by solid state reaction of $Li_2CO_3$ with the manganese oxide or iron-manganese oxide precursors. Investigations of the structure transformation effect of double substitution with $Li^+$ and $Fe^{3+}$ ions in $LiMn_2O_4$, in the temperature range of 10-300 K, were undertaken using high-resolution X-ray powder diffraction at the HASYLAB (DESY) synchrotron. The $Li_{1.0125}Mn_{1.9625}Fe_{0.025}O_4$ transforms from cubic (Fd3̅ m) to orthorhombic (Fddd) below 250 K, and is stable to 10 K. Whereas in the $Li_{1.0125}Mn_{1.9375}Fe_{0.05}O_4$ oxide no phase transition was observed, this spinel remains in cubic structure down to the temperature of 10 K.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 2; 375-382
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical Properties of Europium Compounds with L- and DL-α-Alanine-Hydroxamic Acids
    Autorzy:
    Legendziewicz, J.
    Gawryszewska, P.
    Gałdecka, E.
    Gałdecki, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945683.pdf
    Data publikacji:
    1996-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.Wc
    78.55.Hx
    61.66.Fn
    78.20.Dj
    Opis:
    Two of europium complexes with L- and DL-α-alanine-hydroxamic acids were synthesized. To our knowledge they are the first examples of X-ray and spectral data of lanthanide single crystals with hydroxamic acid derivatives. Both compounds consist of dimers in their structures, formed by two OH bridging groups of amino-hydroxamic acid molecules. Besides, two metal ions are chelated by CO and OH groups, forming five-membered rings. In the complex with L-ligand, different than in the DL-one, two additional perchloric acid molecules are included in crystal cavities and form hydrogen bondings with nitrogen and oxygen atoms of the ligand. Absorption, emission and excitation spectra were measured and analyzed at room and low temperatures. Structural effect of ligand chirality was found and its spectroscopic consequences are reported. The effect of the dimeric structure on spectroscopic properties is discussed.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 2; 439-446
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal Behaviour of PrCo_{1-x}Fe_xO₃ Probed by X-ray Synchrotron Powder Diffraction and Impedance Spectroscopy Measurements
    Autorzy:
    Pekinchak, O.
    Sugak, D.
    Ubizskii, S.
    Suhak, Yu.
    Fritze, H.
    Vasylechko, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1029711.pdf
    Data publikacji:
    2018-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    61.05.cp
    65.40.De
    72.60.+g
    Opis:
    Crystal structure and transport properties of the mixed praseodymium cobaltites-ferrites PrCo_{1-x}Fe_xO₃ have been studied in the temperature range of 298-1173 K by a combination of in situ X-ray synchrotron powder diffraction and temperature dependent impedance spectroscopy measurements. In situ high temperature powder diffraction examination of PrCo_{1-x}Fe_xO₃ series revealed considerable anomalies in the lattice expansion which are especially pronounced for the cobalt-rich specimens. These anomalies, which are reflected in a sigmoidal dependence of the unit cell dimensions and in the considerable increase of the thermal expansion coefficients, are obviously associated with transitions of Co^{3+} ions from low spin to the higher spin states and the coupled metal-insulator transitions, occurring in in rare earth cobaltites at the elevated temperatures. Indeed, the temperature-dependent impedance measurements clearly prove the change of conductivity type from dielectric to the metallic behaviour in the mixed cobaltite-ferrites PrCo_{1-x}Fe_xO₃ at the elevated temperatures.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 4; 798-801
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Mössbauer Spectroscopy and Analytical Investigations οf the Polycrystalline Compounds with General Formula $Zn_xSn_yCr_zSe_4$
    Autorzy:
    Jendrzejewska, I.
    Hanc, A.
    Zajdel, P.
    Kita, A.
    Goryczka, T.
    Maciążek, E.
    Mrzigod, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811602.pdf
    Data publikacji:
    2008-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    61.66.Fn
    75.50.Ee
    82.80.Ej
    Opis:
    We present combined X-ray powder diffraction and Mössbauer $\text{}^{119}Sn$ studies of polycrystalline compounds with a general formula $Zn_xSn_yCr_zSe_4$ (where x+y+z ≈3). The obtained single-phase compounds crystallize in the spinel cubic structure - Fd3m. Tin ions are found to occupy both tetrahedral and octahedral sublattices. On the contrary to the strong tetrahedral site preference energy of Sn, the presented data strongly suggest that the increase in lattice parameters with Sn doping is caused by Sn ions that incorporated into octahedral positions. A quadrupole and isomer shifts of $\text{}^{119}Sn$ in $(SnSe_4)^{6-}$ and $(SnSe_6)^{4-}$ are also reported.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 6; 1591-1597
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Mössbauer and X-Ray Studies οf the Spinel Ferrites $Cu_{0.5}Fe_{0.5}Cr_2Se_4$ and $Cu_{0.2}Fe_{0.8}Cr_2Se_4$ Prepared by the Ceramic Method
    Autorzy:
    Maciążek, E.
    Hanc, A.
    Sitko, R.
    Zawisza, B.
    Jendrzejewska, I.
    Mrzigod, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811603.pdf
    Data publikacji:
    2008-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    61.66.Fn
    82.80.Ej
    75.50.Gg
    Opis:
    Seleno-spinels with nominal chemical composition $Cu_{0.5}Fe_{0.5}Cr_2Se_4$ and $Cu_{0.2}Fe_{0.8}Cr_2Se_4$ were prepared as polycrystalline samples using ceramic method. The assumed composition was verified by wavelength-dispersive X-ray fluorescence spectrometry. The X-ray analysis was carried out in order to make phase analysis and to compare its results with those obtained with the Mössbauer spectroscopy.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 6; 1599-1603
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On Some Structural and Spectroscopic Aspects of Rare Earth Oxycompounds
    Autorzy:
    Hölsä, J.
    Säilynoja, E.
    Porcher, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952800.pdf
    Data publikacji:
    1996-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.10.-i
    61.12.-q
    61.50.-f
    61.66.Fn
    Opis:
    The aim of this account is to present the use and the advantages of different experimental and theoretical methods in the study of the structural and spectroscopic properties of rare earth (RE) oxyfluorides. The structural characterization was carried out with the X-ray and neutron powder diffraction techniques combined with the analysis of the acquired data with the Rietveld profile refinement method. The detailed spectroscopic studies were also used by employing the optical absorption and luminescence as well as inelastic neutron scattering data. Simple spectroscopic measurements gave, however, only qualitative description of the spectroscopic properties studied. More sophisticated and quantitative means was obtained by the application of the phenomenological crystal field theory to the spectroscopic data. On the other hand, the structural data was also used as initial input to electrostatic point charge calculation in order to extract the spectroscopic information. The structural and spectroscopic studies comprised the verification of the exact crystal and energy level structures and the characterization of the different interactions modifying the spectroscopic properties of the RE$\text{}^{3+}$ ions. Finally, the results from the theoretical model were used to explain the evolution of the crystal field effect on the 4f$\text{}^{N}$ energy level structure of the RE$\text{}^{3+}$ ion in the RE oxyfluorides series.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 6; 1193-1201
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A System of B-C-N-O: Synthesis, Characterization and Determination of Unit Cell Parameters
    Autorzy:
    Gül, G.
    Kurtuluş, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033375.pdf
    Data publikacji:
    2017-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    33.20.Ea
    61.66.-f
    61.66.Fn
    84.40.-x
    Opis:
    Boron-rich solids are good candidates to apply instead of diamond. Boron has a unique crystal structure and compounds of it are resistant to heat treatment. These structures have light density, high hardness, and chemically inertness. Also, boron compounds display thermal and electronic properties as a thermoelectric power at high temperatures. A boron, carbon, nitrogen, and oxygen containing compound was synthesized for the first time by classical microwave method using elemental amorphous boron, active carbon, and urea with 1:1:1 molar ratio. The compound is crystallized in monoclinic system with unit cell parameters a=12.9575 Å, b=9.3264 Å, c=9.6529 Å, β =113.277° which are calculated by POWD indexing program. The X-ray diffraction, POWD, the Fourier transform infrared, scanning electron microscopy/energy X-ray diffraction spectroscopy and thermogravimetric/different thermal analysis were achieved.
    Źródło:
    Acta Physica Polonica A; 2017, 131, 1; 36-38
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    $BiFeO_3$ Crystal Structure at Low Temperatures
    Autorzy:
    Palewicz, A.
    Sosnowska, I.
    Przeniosło, R.
    Hewat, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1538869.pdf
    Data publikacji:
    2010-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.fm
    61.66.Fn
    75.50.Ee
    77.84.Bw
    Opis:
    The crystal and magnetic structure of $BiFeO_3$ have been studied with the use of high resolution neutron diffraction between 5 K and 300 K. The atomic coordinates in $BiFeO_3$ are almost unchanged between 5 K and 300 K.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 2; 296-301
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photocatalytic Properties of Mechanochemically Synthesized Nanocrystalline $ZnAl_2O_4$ and CdSe
    Autorzy:
    Kostova, N.
    Eliyas, Al.
    Fabián, M.
    Achimovičová, M.
    Baláž, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1375494.pdf
    Data publikacji:
    2014-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.20.-n
    61.05.cp
    61.46.-w
    61.66.Fn
    Opis:
    Nanocrystalline powders of $ZnAl_2O_4$ and CdSe were prepared via mechanochemical synthesis. Powder slurries were coated as thin films on $SiO_2$ thin layer chromatography (TLC) sheet by capillary method. The photocatalytic activity of the film coating was tested in a self-made gas-phase flat-plate continuous-flow photocatalytic reactor with toluene as model air contaminant. The tested nanocrystalline $ZnAl_2O_4$ turned out to be poor oxidation photocatalyst under UV irradiation. CdSe displays considerable photocatalytic activity under visible light, where $TiO_2$ is inactive. The nonconventional one-step mechanochemical route to $ZnAl_2O_4$ and CdSe synthesis offers several advantages compared to traditional processing routes, including low-temperature solid state reactions at ambient temperature, absence of organic templates contamination and low expenses.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 4; 967-970
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure Prediction for PbS and ZnO at Different Pressures and Visualization of the Energy Landscapes
    Autorzy:
    Zagorac, D.
    Schön, J.
    Doll, K.
    Jansen, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1502980.pdf
    Data publikacji:
    2011-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.50.Ah
    61.66.Fn
    61.50.Ks
    71.50.Nc
    Opis:
    An important issue in modern solid state chemistry is the development of a general methodology to predict the possible (meta)-stable modifications of a solid. This requires the global exploration of the energy landscape of the chemical system, since each stable phase corresponds to a locally ergodic region of the landscape. The global search in the lead sulfide system has been performed with simulated annealing on the ab initio level, while zinc oxide was studied with an empirical potential using simulated annealing, both at standard and elevated pressure (up to 100 GPa). The local optimization of the modifications found in the PbS system was performed using various density functionals. Next, the energy E(V) and enthalpy H(p) as function of volume and pressure, respectively, were computed for these modifications and their electronic structure was analyzed. The structures found for ZnO were locally optimized on ab initio level (DFT and Hartree-Fock). In both systems the structures found were in good agreement with the experiment. Furthermore, we employed the threshold algorithm to explore the barrier structure of the landscape of ZnO as function of the number of formula units in the simulation cell. Based on the barrier and minima information 2-D models of the energy landscape were constructed.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 2; 215-220
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural and Mössbauer Effect Studies of $0.5Bi_{0.95}Dy_{0.05}FeO_{3}-$$0.5Pb(Fe_{2//3}W_{1//3})O_{3}$ Multiferroic
    Autorzy:
    Stoch, A.
    Zachariasz, P.
    Stoch, P.
    Kulawik, J.
    Maurin, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1506596.pdf
    Data publikacji:
    2011-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    61.66.Fn
    75.50.Ee
    77.84.Lf
    Opis:
    A polycrystalline ceramic of $0.5Bi_{0.95}Dy_{0.05}FeO_{3}-$ $0.5Pb(Fe_{2//3}W_{1//3})O_{3}$ was synthesized from a solid-state reaction method. At room temperature material exhibits both magnetic and electric dipolar properties simultaneously. Detailed X-ray diffraction analysis and Mössbauer effect studies have been done to determine the crystallographic structure and magnetic properties of $0.5Bi_{0.95}Dy_{0.05}FeO_{3}-$ $0.5Pb(Fe_{2//3}W_{1//3})O_{3}$. $T_{N}$ temperature was estimated at around 600 K.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 1; 59-61
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetic and Structural Study of $Mn_{1.15}Fe_{0.85}P_{1-x}Ge_{x}$ (0.25 < x < 0.32) Magnetocaloric Compounds Prepared by Arc Melting
    Autorzy:
    Hawelek, L.
    Wlodarczyk, P.
    Zackiewicz, P.
    Polak, M.
    Kaminska, M.
    Puźniak, R.
    Radelytskyi, I.
    Kolano-Burian, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1402326.pdf
    Data publikacji:
    2015-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.30.Sg
    75.30.Kz
    61.05.C-
    61.66.Fn
    Opis:
    Recently, room temperature magnetocaloric materials increasingly attracted attention in the development of magnetic refrigerators. In this paper, an effect of P/Ge substitution on the magnetic phase transition in the series of $Mn_{1.15}Fe_{0.85}P_{1-x}Ge_{x}$ (0.25 < x < 0.32) magnetocaloric compounds prepared by the arc melting technique and subsequent homogenization process has been studied. Calorimetric and magnetization results show that the temperature of structural phase transition coincide with the Curie temperature and fall within the temperature range 270-355 K. The magnetic entropy change reaches the maximum value for the compound with x=0.28 and equals to 32 J/(kg K) for the magnetic field change of 5 T. The adiabatic temperature change for the same sample, measured using magnetocalorimeter, is equal to 1.2 K for the magnetic field change of 1.7 T. It was found that the increase of Ge content in the sample causes weakening of first order magnetic transition, which is manifested by the lowering difference in transition temperature measured in two zero-field-cooling and field-cooled-cooling regimes.
    Źródło:
    Acta Physica Polonica A; 2015, 128, 1; 76-80
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure and Spectroscopy of Selected Lanthanide Compounds with Coordination Number from 9 to 6
    Autorzy:
    Legendziewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945488.pdf
    Data publikacji:
    1996-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    78.20.Dj
    78.20.Wc
    78.55.Hx
    78.66.-w
    Opis:
    The lecture deals with a group of lanthanide compounds in which some structural factors influence, in a special way, spectroscopic properties of the systems under investigation. The following systems were chosen: three with polymeric structure, two of the dimer type, one a pseudo-dimer system with coordination number (C.N.) = 7, and an octahedral compound of LnL$\text{}_{6}$ type. The crystal structures of the systems under consideration will be shown, their absorption and excitation spectra will be presented and confronted with X-ray data. Radiative and nonradiative processes will be considered and the role of cooperative interactions analyzed. Some aspects of dynamics in solids will be done, too.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 1; 127-142
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical Properties and Structure of Ln(NCS)(Hmpa)$\text{}_{4}$-(SCN)$\text{}_{2}$- HgCl(SCN)
    Autorzy:
    Gałdecka, E.
    Gałdecki, Z.
    Amirkhanov, V.
    Kern, K.
    Legendziewicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945687.pdf
    Data publikacji:
    1996-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.Wc
    78.55.Hx
    78.20.Dj
    78.66.-w
    61.66.Fn
    Opis:
    Praseodymium, neodymium and europium complexes of the formula Ln(NCS)(Hmpa)$\text{}_{4}$-(SCN)$\text{}_{2}$-HgCl(SCN) were synthesised from non-aqueous solutions. The structure of neodymium complexes was determined by X-ray diffraction. The crystals of the title compounds crystallise in the space group Cc, where lanthanide ions are coordinated to seven ligand groups: four of Hmpa molecules and three SCN¯ ions. The compounds were characterised by IR, luminescence, excitation and absorption spectra at 6, 77, and 298 K. Probabilities of electronic transitions for Pr$\text{}^{3+}$ ion were examined at 6 K and at room temperatures. Vibronic components were observed and analysed on the basis of IR and Raman data. Asymmetric arrangement of Ln ions was found from X-ray analysis and its influence on optical properties of active centre was discussed.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 2; 469-476
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nuclear Magnetic Resonance in Hexaferrite/Maghemite Composite Nanoparticles
    Autorzy:
    Křišťan, P.
    Hondlík, O.
    Štěpánková, H.
    Chlan, V.
    Kouřil, K.
    Řezníček, R.
    Pollert, E.
    Veverka, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1386884.pdf
    Data publikacji:
    2015-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.60.-k
    75.50.Gg
    75.50.Tt
    75.47.Lx
    61.66.Fn
    Opis:
    Due to their bio-compatibility and non-toxicity, ferrimagnetic iron oxides are suitable for various medical applications. In the case of hyperthermia, the promising approach how to reach desired magnetic properties is to combine more phases into a composite material. A series of samples containing maghemite and M-hexaferrite was prepared by sol-gel method with subsequent thermal treatment where annealing temperature and time were varied. The samples were characterized by X-ray diffraction. In this paper we focused mainly on application of nuclear magnetic resonance spectroscopy to investigate these strongly inhomogeneous nanoparticle composites. Frequency-swept ⁵⁷Fe NMR spectra of nanoparticle samples were measured in a zero external magnetic field at 4.2 K. Utilizing differences in optimal excitation field strengths and in relaxation times, we were able to resolve NMR signal assigned to hexagonal ferrite of M-phase from signal which showed features attributed to maghemite.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 2; 514-516
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural and Mössbauer Effect Studies of $0.7Bi_{0.95}Dy_{0.05}FeO_3-$$0.3Pb(Fe_{0.5}Nb_{0.5})O_3$ Multiferroic
    Autorzy:
    Stoch, A.
    Kulawik, J.
    Stoch, P.
    Maurin, J.
    Zachariasz, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1506595.pdf
    Data publikacji:
    2011-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    61.66.Fn
    75.50.Ee
    76.08.+y
    77.84.Lf
    Opis:
    $0.7Bi_{0.95}Dy_{0.05}FeO_{3}-$ $0.3Pb(Fe_{0.5}Nb_{0.5})O_{3}$ is a multiferroic material which exhibits ferroelectric and antiferromagnetic ordering. In this paper the way of the synthesis of $0.7Bi_{0.95}Dy_{0.05}FeO_{3}-$ $0.3Pb(Fe_{0.5}Nb_{0.5})O_{3}$ is presented. The detailed X-ray and Mössbauer effect studies were done and crystal and hyperfine interaction parameters were obtained.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 1; 56-58
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation study of topological point defects in graphitic layer - curvature effect and pair correlation function analysis
    Autorzy:
    Hawelek, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1075560.pdf
    Data publikacji:
    2016-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.ue
    61.72.J-
    61.43.Bn
    61.66.Fn
    61.05.C-
    Opis:
    The effect of three types of topological defects, single vacancy, double vacancy and the Stone-Thrower-Wales defect on the atomic arrangement in a single graphitic layer is studied using computer simulations. The topological defects were positioned on the perfect hexagonal graphitic layer 20 Å in diameter with different distance from the layer edge and then the geometry of the system was independently optimized using the reactive bond order potential, the semi-empirical quantum-chemical PM7 and the density functional theory method. Curvature and the distortion of the graphitic layer caused by the defects are analyzed and their influence on the pair correlation function is discussed.
    Źródło:
    Acta Physica Polonica A; 2016, 130, 3; 811-816
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low Temperature Crystal Structure Behaviour of Complex Yttrium Aluminium Oxides YAlO_3 and Y_3Al_5O_{12}
    Autorzy:
    Senyshyn, A.
    Vasylechko, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399474.pdf
    Data publikacji:
    2013-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    61.05.F-
    65.40.De
    65.60.+a
    63.70.+h
    Opis:
    Crystal structures of two yttrium aluminium oxides, namely $YAlO_3$ and $Y_3Al_5O_{12}$, were investigated in the temperature range 3.4-300 K by high-resolution neutron powder diffraction. Neither traces of phase transformations nor discontinuous changes of physical properties were observed. Thermal expansion of yttrium aluminium oxides was evaluated in terms of 1st order Grüneisen approximation, where the Debye temperatures and the Grüneisen parameters have been estimated for both compositions. Anomalies in the thermal expansion of yttrium aluminium perovskite have been observed and modelled using the Einstein oscillator with negative Grüneisen parameter. Extended bond length analysis revealed significant thermally-driven modifications of the aluminium-oxygen framework.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 2; 329-335
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Carbonaceous Materials Obtained from Sewage Sludge for $NO_2$ Removal under Wet Conditions at Room Temperature
    Autorzy:
    Pietrzak, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1536471.pdf
    Data publikacji:
    2010-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.66.Fn
    81.05.-t
    81.05.Rm
    82.65.+r
    89.60.-k
    Opis:
    The effect of the processes of carbonisation and activation on adsorbents obtained from sewage sludge and their sorption properties towards $NO_2$ were studied. Carbonaceous adsorbents were obtained by carbonisation of sewage sludge at 600°C for four different times 30, 60, 90 and 120 min followed by activation of the carbonisates by $CO_2$ at 800°C for 60 min. Adsorption of $NO_2$ was carried out in wet air. It has been shown that by appropriate thermal and chemical treatment of sludge, mesoporous adsorbents capable of $NO_2$ removal can be obtained. The sorption abilities of the carbonised and activated samples to adsorb $NO_2$ have been shown to increase with increased time of carbonisation and reach maximum for the carbonisation maintained for 90 min. Further increase in this time causes a decrease in the adsorption abilities of the samples. The sorption properties of the carbonisates have been proved to be determined by the chemical character of the surface, while those of the activated samples - by the porous structure.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 3; 487-492
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electronic Constitution of Paramagnetic 3d Complexes and Positronium Conversion Rate Constants
    Autorzy:
    Fantola Lazzarini, A. L.
    Lallarini, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/1929063.pdf
    Data publikacji:
    1993-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    36.10.Dr
    61.66.Fn
    71.70.Ch
    78.40.Dw
    78.70.Bj
    Opis:
    The rate constants, k$\text{}_{SE}$, of ortho- into para-positronium spin conversion reactions promoted by paramagnetic 3d complexes may be correlated with their electronic constitution as it is described by the spin-orbit coupling and interelectronic repulsion parameters. The correlation is explained in terms of unpaired metal-electron delocalization towards the complex boundaries.
    Źródło:
    Acta Physica Polonica A; 1993, 83, 3; 297-302
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Vibration and Luminescence Spectroscopic Investigations of the Alkali Rare Earth Double Phosphates M$\text{}_{3}$(RE,Eu)(PO$\text{}_{4}$)$\text{}_{2}$ (M=K, Rb; RE=La, Gd)
    Autorzy:
    Kloss, M.
    Schwarz, L.
    Hölsä, J. P. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1995573.pdf
    Data publikacji:
    1999-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.50.-f
    61.66.Fn
    63.20.-e
    71.20.Dg
    71.20.Eh
    71.70.-d
    78.30.-j
    78.55.-m
    Opis:
    The room temperature IR- and Raman spectra of the different M$\text{}_{3}$RE(PO$\text{}_{4}$)$\text{}_{2}$ (M = K, Rb; RE = La, Eu, Gd) double phosphates were analysed and used to interpret the vibronic side band structure in the photoluminescence spectra. The intraconfigurational 4f-4f electronic transitions in the photoluminescence spectra of the Eu$\text{}^{3+}$ doped M$\text{}_{3}$RE(PO$\text{}_{4}$)$\text{}_{2}$ were analysed in detail. The crystal field fine structure of the $\text{}^{5}$D$\text{}_{0}$ → $\text{}^{7}$F$\text{}_{J}$ (J=0-4) transitions was analysed accounting for the information on the crystal structure. The effect of the temperature as well as the alkali host cation was evaluated. Finally, a preliminary crystal field energy level scheme for the $\text{}^{7}$F$\text{}_{J}$ (J=0-4) ground term was deduced from the analysis of the photo-luminescence as well as IR- and Raman spectra.
    Źródło:
    Acta Physica Polonica A; 1999, 95, 3; 343-349
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Novel Route to Prepare Magnetic Material $Co_3V_2O_8$ and Structural Characterization
    Autorzy:
    Celik, G.
    Kurtulus, F.
    Guler, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1491310.pdf
    Data publikacji:
    2012-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    07.85.-m
    32.30.Rj
    33.20.Ea
    61.43.Gt
    61.66.Fn
    65.40.-b
    75.47.Lx
    81.40.Gh
    82.33.Pt
    84.40.-x
    Opis:
    $Co_3V_2O_8$ is a member of kagomé staircase oxides, represented by general formula $M_3V_2O_8$ (M = Ni, Co, Mn). It attracted great attention due to strong magnetic anisotropy, magnetic phase transition, genuine macroscopic quantum effects, strong quantum fluctuations, low-temperature ferroelectricity, field-induced magnetic transitions, complicated phase diagram and displays long-range magnetic order because of geometrical frustration. Different routes to prepare the frustrated magnetic material was reported such as floating zone technique and conventional high temperature method. $Co_3V_2O_8$ (International Centre for Diffraction Data (ICDD): 16-675) was synthesized with $Co_3O_4$ (ICDD: 80-1536) as binary phase by microwave assisted preparation using $Co(NO_3)_2 ·6H_2O$ and $NH_4VO_3$. The synthesized material was characterization by powder X-ray diffraction, the Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 1; 203-204
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-42 z 42

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