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Wyszukujesz frazę "61.50.+f" wg kryterium: Temat


Wyświetlanie 1-35 z 35
Tytuł:
EPR Study of VO$\text{}^{2+}$ Center in Fast Proton Conductor K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$
Autorzy:
Ostrowski, A.
Waplak, S.
Bednarski, W.
Powiązania:
https://bibliotekanauki.pl/articles/2043409.pdf
Data publikacji:
2005-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
76.30.-v
Opis:
The pretransitional phenomena of superprotonic phase transition (T$\text{}_{sp}$=471 K) were studied in detail by X-band continuous wave EPR spectra of K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ crystal doped with VO$\text{}^{2+}$ ions. Three kinds of VO$\text{}^{2+}$ complexes (magnetically equivalent but structurally non-equivalent) denoted as VO$\text{}^{2+}$(I), VO$\text{}^{2+}$(II), and VO$\text{}^{2+}$(III) were found. "Smearing out" of the superhyperfine structure was observed as a result of interbond proton motion. VO$\text{}^{2+}$ impurity replaces K$\text{}^{+}$ ion and experiences the same average crystal field gradient at T$\text{}_{sp}$=471 K for I- and II-type complexes. The increase in interbond proton frequency hopping above 360 K is a reason of significant line broadening.
Źródło:
Acta Physica Polonica A; 2005, 108, 1; 127-135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of Phase Transitions in (NH$\text{}_{4}$)$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ Crystal by Means of Mn$\text{}^{2+}$ EPR Spectra
Autorzy:
Bednarski, W.
Waplak, S.
Powiązania:
https://bibliotekanauki.pl/articles/1952756.pdf
Data publikacji:
1996-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
76.30.-v
Opis:
EPR of Mn$\text{}^{2+}$ impurity ion in the (NH$\text{}_{4}$)$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ crystal is studied in the temperature range 80-420 K. It is shown that Mn$\text{}^{2+}$ substitutes NH$\text{}_{4}^{+}$(I) ion and is coordinated in deformed oxygen octahedron in which takes two "off-center" positions. Its spin-Hamiltonian parameters and direction cosines of crystal field are determined. The successive EPR line splitting for three phase transitions is discussed.
Źródło:
Acta Physica Polonica A; 1996, 90, 6; 1185-1192
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR Application in the Study of K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ Proton Conductor Doped with Mn$\text{}^{2+}$ or VO$\text{}^{2+}$ Ions
Autorzy:
Waplak, S.
Powiązania:
https://bibliotekanauki.pl/articles/1931810.pdf
Data publikacji:
1994-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
76.30.-v
Opis:
The EPR of Mn$\text{}^{2+}$- or VO$\text{}^{2+}$-doped superprotonic conductor K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ is studied in the 80-471 K temperature range. VO$\text{}^{2+}$ EPR spectrum reveals diffusion induced merging of proton transferred superhyperfine structure above 380 K. Line width anomaly is observed in Mn$\text{}^{2+}$ EPR spectrum which is attributed to the intrabond and interbond proton motions, these lead to high protonic conductivity. It is shown that paramagnetic centers namely of electronic spin greater than 1, with excess charge compensated by the protonic vacancy, are good probes to monitor the protonic conductivity on molecular level.
Źródło:
Acta Physica Polonica A; 1994, 86, 6; 939-945
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR Study of Cu$\text{}^{2+}$ Doped Fast-Proton Conductor K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ in the Temperature Range 100-450 K
Autorzy:
Ostrowski, A.
Bednarski, W.
Waplak, S.
Powiązania:
https://bibliotekanauki.pl/articles/2037037.pdf
Data publikacji:
2003-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
76.30.-v
Opis:
The K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ doped with Cu$\text{}^{2+}$ ion was studied in detail by X-band CW EPR. Two kinds of Cu$\text{}^{2+}$ complexes (magnetically and structurally nonequivalent) denoted as Cu$\text{}^{2+}$(I) and Cu$\text{}^{2+}$(II) were found. Spin-Hamiltonian parameters, direction cosines, and coordination of Cu$\text{}^{2+}$ ion were determined at room temperature. The superhyperfine structure was observed below 250 K as a result of interacting of Cu$\text{}^{2+}$ ion with four equivalent protons (I=1/2). Temperature studies of K$\text{}_{3}$H(SO$\text{}_{4}$)$\text{}_{2}$ crystal show that interbond motion as a precursor of superprotonic phase transition occurs at above≈250 K.
Źródło:
Acta Physica Polonica A; 2003, 104, 6; 549-558
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Doping on the Structural Distortion of $La_{0.7}Dy_{0.3}Mn_{1-x}Zn_xO_3$
Autorzy:
López, J.
Ríos, M.
Mendoza, G.
Powiązania:
https://bibliotekanauki.pl/articles/1398317.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
61.50.-f
Opis:
Structural properties were studied in the orthorhombic perovskite $La_{0.7}Dy_{0.3}Mn_{1-x}Zn_{x}O_3$, synthesized in the range 0 ≤ x ≤ 0.4. X-ray diffraction data, refined by the Rietveld analysis, shows for x < 0.1 the presence of stretched octahedra on the Mn-O plane, and, for x > 0.1, the existence of elongated octahedra along the c axis. Increased Zn doping causes a direct structural effect: one Zn atom distorts four neighboring MnO₆ octahedra on the Mn-O plane. It was observed that the unit cell volume containing Dy decreases as x increases, whereas the unit cell volume containing La increases as x decreases.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1254-1255
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of "exotic" dopant-related macrodefects in vapour grown CdTe:Cr single crystals
Autorzy:
Popovych, V.
Sagan, P.
Powiązania:
https://bibliotekanauki.pl/articles/1075546.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
61.72.-y
61.72.Vv
Opis:
SEM observation of non-typical macrodefects in the form of needle-like second phase particles in highly doped CdTe:Cr single crystals, grown by the modified physical vapour transport method, was reported. They form regular network parallel to the {111} and {100} planes. In the combined analyses using energy dispersive X-ray profiling and high-angle annular dark-field elemental mapping, it has been determined that the observed needle-like aggregates are composed of Cr-Te intermetallic compound, most probably cadmium doped Cr₃Te₄.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 49-51
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic, Thermal and Transport Properties of $YbPt_2Si_2$ and $Yb_2Pt_3Si_5$ Single Crystals
Autorzy:
Fikáček, J.
Prchal, J.
Sechovský, V.
Powiązania:
https://bibliotekanauki.pl/articles/1371255.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
75.20.En
75.30.Mb
Opis:
Single crystals of $YbPt_{2}Si_{2}$ and $Yb_{2}Pt_{3}Si_{5}$ have been prepared by solvent growth method with Sn flux, characterized by X-ray diffraction and by EDX microprobe analysis and investigated by measurement of magnetization, specific heat and electrical resistivity as functions of temperature and magnetic field. $YbPt_{2}Si_{2} (Yb_{2}Pt_{3}Si_{5})$ crystalizes in the tetragonal $CaBe_{2}Ge_{2}$-type (orthorhombic $U_{2}Co_{3}Si_{5}$-type) structure. Both compounds exhibit metallic resistivity behavior without visible anomaly, which could be connected with onset of magnetic ordering. Neither the specific heat shows any sign of magnetic ordering down to 0.5 K. The corresponding temperature dependences of the magnetic susceptibility of both compounds behave qualitatively similar, which is reminiscent of spin fluctuation behavior: a broad maximum at high temperatures, a shallow minimum at lower temperatures, followed by an upturn with further cooling the crystal, which can be suppressed by applying a sufficient magnetic field. The rather low values of the γ-coefficients of the specific heat (~25÷35 mJ·mol·$K^{-2}$) do not support the mixed valence scenario discussed in literature for $YbPt_{2}Si_{2}$.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 310-311
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudorotational Averaging of EPR Spectrum of Cu(II)O$\text{}_{5}$ Complex in YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ in Low Temperatures
Autorzy:
Stankowski, J.
Kempiński, W.
Trybuła, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1891644.pdf
Data publikacji:
1991-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
74.70.Vy
76.30.Fe
Opis:
In low temperatures the condensation of oxygen was found to occur at 05 site in an elementary cell of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ being the fifth ligand forming the CuO$\text{}_{5}$ complex around Cul copper in chain. This change of coordinantion from CuO$\text{}_{4}$ to CuO$\text{}_{5}$ is the origin of a pseudorotation related to a strong vibronic coupling of two distorted configurations: a tetragonal pyramid C$\text{}_{4v}$ and a trigonal bipyramid D$\text{}_{3h}$, which yields a pseudocubic EPR spectrum in low temperatures. The averaged spectroscopic splitting coefficient is related to a superposition of vibronically coupled orbital states |x$\text{}^{2}$ - y$\text{}^{2}$〉 and |3z$\text{}^{2}$ - r$\text{}^{2}$〉. The averaged spectrum was for the first time observed in low temperatures since the oxygen condensation in YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ at 05 site of the chain occur only when oxygen undergoing fast diffusion among the chains, gets localized with decreasing temperature. The activation energy of oxygen desorption from the 05 site is 36 K.
Źródło:
Acta Physica Polonica A; 1991, 80, 4; 571-581
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XRD Analysis of Synthetic Diamond Powders Irradiated with Electrons
Autorzy:
Shishonok, E.
Luhin, V.
Koltunowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402231.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.-a
61.43.Gt
61.50.-f
61.80.Fe
Opis:
Powders of synthetic diamond with low strength were sorted on sets with a different grain size. The synthetic diamond sets had various crushing strengths and morphology. They were irradiated with high energy electrons (6.5 MeV, D=2×10¹⁹ cm¯²) and analyzed using X-ray diffraction (Cu K_α) before and after irradiation. As established from nonlinearity of the a(Θ)=f{R(Θ)} dependences and observed extra splittings in X-ray diffraction patterns (in addition to α₁-α₂ doublets), crystal lattice of synthetic diamond from different sets was variously distorted. Irradiation led to decreasing distortions more significantly, the higher the initial strength of the set was. The made conclusions coincide well with our previous results on synthetic diamond powders which were irradiated under various softer conditions with direct measurements of synthetic diamond crushing strength without X-ray diffraction analysis. X-ray diffraction allows to presort synthetic diamond of critically low relative mechanical strength as well as evaluate resistance of diamond crystal lattice against heavy irradiation and other external impacts.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 912-914
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:
Analysis of Crystallographic Orientation Changes during Deformation of Magnesium Single Crystals
Autorzy:
Sułkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1205235.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Hh
61.50.-f
81.10.Aj
61.50.Ah
81.40.Ef
Opis:
Magnesium single crystals of three different orientations were deformed by tension at room temperature to investigate the geometrical criterion resulting from the Schmid law for activation of basal and non-basal slip systems. Changes of crystallographic orientations of investigated single crystals were systematically measured during deformation and the geometrical criterion was examined in respect to the changes of crystallographic orientations during deformation. The geometrical criterion itself failed to explain lack of activity of non-basal slip systems in the deformed magnesium single crystals. Therefore the ratio of activation volumes of soft to hard slip systems is considered to be introduced for a better understanding of the deformation in hcp metals.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 768-771
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seebeck Coefficient and Optical Studies of Cadmium Doped $CuInS_{2}$ Single Crystal
Autorzy:
Chaki, S.
Powiązania:
https://bibliotekanauki.pl/articles/1807787.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
72.20.Pa
78.20.-e
61.50.-f
Opis:
Single crystals of $CuInS_{2}$ were successfully grown by chemical vapor transport technique using iodine as transporting agent. The as-grown chemical vapor transport $CuInS_{2}$ single crystals were found to have large resistivity. To decrease the resistivity of the crystals they were doped with three different cadmium concentrations. Seebeck coefficient variation with temperature is measured for all the three doped samples. Optical bandgaps were determined for these three doped samples using optical absorption spectra. The obtained results are discussed in detail.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 221-225
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal structure of the high temperature phase of strontium barium niobate
Autorzy:
Paszkowski, R.
Zubko, M.
Wokulska, K.
Kusz, J.
Dec, J.
Powiązania:
https://bibliotekanauki.pl/articles/1058111.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Mp
77.84.Dy
61.50.-f
71.55.Jv
Opis:
Pure and undoped strontium-barium niobate Sr_{0.40}Ba_{0.60}Nb₂O₆ (SBN40) single crystals grown by the Czochralski method were investigated by single crystal X-ray diffraction methods. The study below T_{C} (429 K for SBN40) confirmed the structure with P4bm space group. Above this temperature the structure transforms into the paraelectric, centrosymmetric one with P4/mbm space group. Analysis of the recorded diffraction patterns allowed to observe several signs of crystal structure modulation. On the registered diffraction images satellite reflections were found. A modulation vector q=(δ,±δ,), where δ=0.3075(6) (at room temperature) was found and it was similar to that occurring in the SBN61. In addition, above the phase transition temperature on the (hk) planes with l integer a weak diffuse scattering was observed.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 856-858
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trapped field of YBCO bulk superconductors prepared by infiltration growth process
Autorzy:
Vojtkova, L.
Diko, P.
Piovarči, S.
Powiązania:
https://bibliotekanauki.pl/articles/1054776.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.81.Bd
61.50.-f
74.25.Ha
81.10.Fq
Opis:
Single grain Y₁Ba₂Cu₃O_{7-x} (YBCO) bulk superconductors were prepared from different starting precursors. In the first case, Y₂Ba₁Cu₁O₅ (Y211) powder as the solid phase and the liquid phase of mixture of YBa₂Cu₃O_{7-x}+BaCuO₂+CuO powders were used. In the second case, the solid phase was prepared from the mixture of Y₂O₃+BaCuO₂ instead of the conventionally used Y211, and as the liquid phase a mixture of Y₂O₃+BaCuO₂+CuO powders was used. The trapped field measurements at 77 K were performed and microstructure of samples was studied by polarized light microscopy. The positive influence of Y₂O₃+BaCuO₂ starting precursor on the oxygenation, Y211 particle refinement and measured trapped field is shown.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1048-1050
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infinite Body Centered Cubic Network of Identical Resistors
Autorzy:
Asad, Jihad
Diab, A.
Owaidat, M.
Hijjawi, R.
Khalifeh, J.
Powiązania:
https://bibliotekanauki.pl/articles/1206306.pdf
Data publikacji:
2014-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ah
61.50.+f
61.66.f
84.37.+q
05.50.+q
04.60.Nc
63.90.+t
84.30.Bv
02.90.+p
Opis:
We express the equivalent resistance between the origin (0,0,0) and any other lattice site ($n_1$,$n_2$,$n_3$) in an infinite body centered cubic network consisting of identical resistors each of resistance R rationally in terms of known values $b_{0}$ and π. The equivalent resistance is then calculated. For large separations two asymptotic formulae for the resistance are presented and some numerical results with analysis are given.
Źródło:
Acta Physica Polonica A; 2014, 125, 1; 60-64
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:
High Pressure Phase Transition and Allied Behavior οf Samarium Compounds
Autorzy:
Singh, M.
Gour, A.
Singh, S.
Powiązania:
https://bibliotekanauki.pl/articles/1400142.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ks
61.50.Lt
61.66.-f
62.20.-x
Opis:
A theoretical study of the phase transition of samarium monochalcogenides using three-body interaction potential model is carried out at high pressure. The three-body interaction potential includes long range Coulombic, three-body interaction forces and short range overlap repulsive forces operative up to next nearest neighbor ions. We have investigated phase transition pressures, volume collapses, elastic behavior, stability criteria and various thermo physical properties at various high pressure. The results found are well suited with available experimental data. In this paper third order elastic constants are also reported for the first time which helps in understanding the nature of interionic forces in ionic solids which paved the experimentalist to work in specific direction.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 709-713
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manganites - Structural Aspects
Autorzy:
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1536851.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cp
61.05.F-
61.05.J-
75.30.kz
75.50.Ee
75.50.-y
Opis:
In the work a brief discussion of the structural and magnetic properties of the manganites from the point of view of the micro- and macrostructures is presented. The influence of stoichiometry with the different oxygen parameter δ and doped atoms is discussed. The correlation between the crystal structure parameters and magnetic properties for some manganites is presented.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 303-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Grain Size on the Magnetic Properties of $TbMnO_{3}$
Autorzy:
Bażela, W.
Dul, M.
Dyakonov, V.
Gondek, Ł.
Hoser, A.
Hoffmann, J.
Penc, B.
Szytuła, A.
Kravchenko, Z.
Nosalev, I.
Zarzycki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1431251.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.Cp
61.05.F-
61.05.J-
75.30.kz
75.50.Ee
75.50.-y
Opis:
The magnetic properties including magnetic structure of poly and nano samples of $TbMnO_{3}$ are determined. All the samples investigated are antiferromagnets. In these samples the Mn ad Tb moments order antiferromagnetically at different temperatures and form modulated magnetic structure described by the propagation vector k=($k_{x}$,0,0) with different value of $k_{x}$ for the Mn and Tb sublattices. Comparison of the data for poly and nano samples indicates the decrease of the moment and increase of the $k_{x}$ component of propagation vector in the nano specimens. The wide Bragg peak related to the Tb sublattice suggests that the magnetic order has the claster-like character. The magnetic moments value in both sublattices is smaller, whereas the $k_{x}$ values are larger for nano samples.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 785-788
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Structure of $(NbSe_4)_3I$ and $(NbSe_4)_{10//3}I$ CDW Compounds at 14 K
Autorzy:
Zubko, M.
Kusz, J.
Prodan, A.
Bennett, J.
Świec, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398362.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Ks
61.05.C-
72.15.Nj
61.72.Mm
61.66.-f
Opis:
Both $(NbSe_4)_3I$ and (NbSe_4)_{10//3}I$ compounds are interesting system possessing quasi one-dimensional linear chain character and exhibiting nonlinear transport properties with a second order phase transition. The compounds are built of $NbSe_4$ antiprisms, stacked along the tetragonal c axis into chains in a screw-like arrangement. Performed X-ray low temperature single crystal diffraction measurements allowed to solve, refine and analyze crystal structures of both compounds at 14 K. While $(NbSe_4)_{10//3}I$ compound undergoes structural phase transition to monoclinic phase, $(NbSe_4)_3 I$ remains in tetragonal symmetry. Iodine atoms are responsible for the differences in $(NbSe_4)_{10//3}I$ and $(NbSe_4)_3 I$ structures causing different spacing in the infinite $NbSe_4$ chains.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 869-872
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Stabilities and Elastic Constants of EuX (X = O, S, Se, and Te) Compounds at High Pressure
Autorzy:
Kong, B.
Zhou, Z.
Sun, X.
Zhang, L.
Ling-Hu, R.
Powiązania:
https://bibliotekanauki.pl/articles/1400144.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.-f
46.70.-p
61.43.-j
75.50.-y
Opis:
The structural stabilities, elastic properties and charge transfers of EuX (X = O, S, Se, Te) compounds as a function of pressure are investigated extensively using first-principles calculations. The ground-state parameters, such as lattice constants, bulk modulus are predicted and compared with the available data, our results are satisfactory. The calculated phase transition pressures from the NaCl-type (B1) structure to the CsCl-type (B2) structure for EuX (X = O, S, Se, Te) also accord with the experiments. Particularly, the elastic constants of EuX (X = O, S, Se, Te) under zero pressure and high pressure are simulated appropriately for the first time via density functional theory. The softening behaviors of the elastic shear modulus $C_{44}$ under pressure for the B1 phase of EuX (X = O, S, Se, Te) are captured, which should be responsible for the pressure-induced structural phase transition in the EuX system. It is also suggested that the softening behavior might be induced partly by the p → d and f → d electron transfers of Eu atom under pressure. In addition, the aggregate elastic modulus (B, G, E), Poisson's ratio (σ), Debye temperature $\Theta p_{D}$ are also successfully obtained for both B1 and B2 phases of EuX.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 720-727
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer Spectrometry in FeMoCuB-Type Nanocrystalline Alloys
Autorzy:
Miglierini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813519.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
61.46.+w
61.66.-f
76.80.+y
Opis:
The applicability of the Mössbauer spectrometry to the study of $Fe_{91-x}Mo_8Cu_1B_x$ (x = 12, 15, 17) nanocrystalline alloys prepared by controlled annealing of ribbon-shaped amorphous precursors is demonstrated. Differences between both surfaces of the ribbons are pointed out to be due to preparation conditions. Conclusions from the Mössbauer spectrometry are supported by diffraction of synchrotron radiation, X-ray diffraction, and atomic field microscopy investigations.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 47-50
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutron Diffraction Studies of Nanoparticle $DyMnO_3$ Compound
Autorzy:
Szytuła, A.
Penc, B.
Dyakonov, V.
Baran, S.
Hoser, A.
Powiązania:
https://bibliotekanauki.pl/articles/1206328.pdf
Data publikacji:
2014-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
75.25.-j
75.50.Ee
Opis:
The neutron powder diffraction (NPD) measurements of the nano-size $DyMnO_3$ manganite have been performed. The obtained results indicate that this compound crystallizes in the orthorhombic crystal structure described by the space group Pnma. The Mn and Dy moments order antiferromagnetically at different temperatures and form modulated magnetic structure described by the propagation vector k=($k_x$, 0, 0) with the different values of $k_x$ component for the Mn and Dy sublattices. The values of $k_x$ component for Mn sublattice increase with decreasing of the temperature and are smaller that in bulk compound. The wide Bragg peaks related to the Dy sublattice suggest that the magnetic order in this sublattice has the cluster-like character.
Źródło:
Acta Physica Polonica A; 2014, 125, 1; 65-66
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photocatalytical Decomposition of Contaminants οn Thin Film Gas Sensors
Autorzy:
Radecka, M.
Łysoń, B.
Lubecka, M.
Czapla, A.
Zakrzewska, K.
Powiązania:
https://bibliotekanauki.pl/articles/1539145.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.-r
73.90.+f
82.50.Hp
Opis:
Gas sensing materials have been prepared in a form of $TiO_{2}-SnO_{2}$ thin films by rf reactive sputtering from $Ti:SnO_{2}$ and $Sn:TiO_{2}$ targets. Material studies have been performed by scanning electron microscopy, atomic force microscopy, X-ray diffraction at grazing incidence, Mössbauer spectroscopy, X-ray photoelectron spectroscopy and optical spectrophotometry. Dynamic gas sensing responses have been recorded as reproducible changes in the electrical resistance upon introduction of hydrogen at a partial pressure of 100-6000 ppm over a wide temperature range 473-873 K. Contamination experiments have been carried out with the motor oil (40 vol.% solution in $CCl_{4}$) in order to study the effect of UV light illumination on the gas sensor response. Optical spectroscopy has been applied to monitor the photodecomposition of the test compound, bromothymol blue. The Electronic Nose, ALPHA MOS FOX 4000 has been used in order to differentiate between different groups of motor oil vapors.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 415-419
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Short Range Order of Two Phases in the Single Domain $Mn_{0.75}Cu_{0.25}$ Alloy after Spinodal Decomposition
Autorzy:
Jankowska-Kisielińska, J.
Świderska, K.
Mikke, K.
Powiązania:
https://bibliotekanauki.pl/articles/1538297.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
75.30.Fv
75.40.-s
75.50.Lk
Opis:
The aim of the present paper was to identify the atomic and magnetic structure and short-range order of the two phases present in the $Mn_{0.75}Cu_{0.25}$ alloy after decomposition and plastic deformation. The sample was investigated by elastic neutron scattering at small-angle and 3-axes spectrometers. We have confirmed the decomposition of the alloy into two types of regions with manganese concentration increased and decreased as compared with the mean value. The crystal lattice in regions of both types is tetragonal (pseudo FCT) below $T_{N}$ but degree of tetragonal distortion is different. The long range antiferromagnetic order is present only in the regions of bigger distortion and higher Mn concentration. In the regions of lower Mn content and smaller distortion there is a short range ordering of complex magnetic and atomic character.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 582-585
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Creep Deformation of Intermetallic TiAl-Based Alloy
Autorzy:
Lapin, J.
Staneková, H.
Powiązania:
https://bibliotekanauki.pl/articles/1418436.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
62.20.F-
81.30.Mh
83.50.-v
Opis:
In the present work, the creep deformation behaviour of a new cast intermetallic Ti-46Al-8Ta [at.%] alloy is analysed. Constant load tensile creep tests were performed at initial applied stresses ranging from 200 to 400 MPa in the temperature range from 973 to 1073 K. The measured creep deformation curves are analysed and the observed deviations from calculated curves are discussed based on microstructural changes observed in the studied alloy during creep. The kinetics of creep deformation are evaluated in terms of the true activation energy for creep and the stress exponent. Creep damage initiation and propagation leading to the fracture of the creep specimens are characterized as functions of the applied stress and temperature.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 453-456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffuse Neutron Scattering in the $Mn_{0.4}Cu_{0.6}$ Alloy
Autorzy:
Jankowska-Kisielińska, J.
Mikke, K.
Fijał-Kirejczyk, I.
Powiązania:
https://bibliotekanauki.pl/articles/1813173.pdf
Data publikacji:
2008-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
75.30.Fv
75.40.-s
75.50.Lk
Opis:
The diffuse neutron scattering in the $Mn_{0.4}Cu_{0.6}$ alloy was measured in the temperature range 15-390K at the 3-axis neutron spectrometer at MARIA reactor in Świerk. The broad maxima of the neutron intensity were observed in the surrounding of the (0.5, 1, 0) reciprocal lattice point and other symmetry related points. The effect is similar to that observed in Mn-Cu alloys with lower Mn content at room temperature. Our results are in agreement with the earlier finding that the maxima of the short-range order incommensurate spin density wave scattering are placed at the (0.5±δ, 1, 0) reciprocal lattice point with a linear dependence of δ on the Mn concentration. In addition, some commensurate antiferromagnetic short-range order was found.
Źródło:
Acta Physica Polonica A; 2008, 113, 4; 1171-1178
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size effects in antiferromagnetic NiO nanoparticles
Autorzy:
Baran, S.
Hoser, A.
Penc, B.
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1075485.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
75.30.Cr
75.47.Lx
75.50.Ee
Opis:
X-ray and neutron diffraction as well as magnetometric methods were used in order to investigate crystal and magnetic structure together with magnetic properties of nickel oxide NiO obtained from thermal decomposition of Ni(OH)₂. It has been found that crystal unit cell volume and crystal unit cell deformation parameter decrease with increasing decomposition temperature T_{d} while grain size increases. The results of magnetization, magnetic susceptibility and neutron diffraction measurements reveal a formation of antiferromagnetic order with uncompensated magnetic moment below the Néel temperature. Magnetization together with coercive field decreases with increasing T_{d}. The neutron diffractogram of sample obtained at 240°C indicates broadening of both the peaks of nuclear and magnetic origin. The magnetic ordering may be described by a propagation vector k=[½,½,½].
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 35-39
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inelastic Neutron Scattering in Sendust Alloy in 8-295 K Temperature Range
Autorzy:
Świderska, K.
Jankowska-Kisielińska, J.
Dobrzyński, L.
Powiązania:
https://bibliotekanauki.pl/articles/1419612.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
75.30.Fv
75.40.-s
75.50.Lk
Opis:
The effects concerning magnetic and nuclear excitations in a single crystal of Sendust alloy (73.5 at.% Fe, 9.5 at.% Al, 17 at.% Si) are discussed. The excitations have been investigated by means of elastic and inelastic neutron scattering with the use of triple axis and small angle spectrometer. A few potential causes of spin wave damping in Sendust, like interactions of excitations or small-size precipitations of different compositions or directions of magnetization were disproved. It is suggested that one- and two-phonon scattering can explain observed strong increase of incoherent inelastic scattering with temperature.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 400-404
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deformation microstructures in metallic materials after severe plastic deformation by rolling with cyclic movement of rolls
Autorzy:
Urbańczyk-Gucwa, A.
Bednarczyk, I.
Jabłońska, M.
Rodak, K.
Powiązania:
https://bibliotekanauki.pl/articles/1075888.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.F-
61.72.Ff
81.05.Bx
81.40.Rs
83.50.-v
Opis:
The results of the microstructure investigations of the pure Al and AlMg5 alloy and pure Cu and CuFe2 alloy after the application of severe plastic deformation implemented by rolling with the cyclic movement of the rolls are presented in this paper. The rolling with the cyclic movement of the rolls was carried out at values: the rolling rate v=1 rpm, the frequency of rolls movement f=1 Hz, the amplitude of rolls movement A=1.6 mm. Maximal values of rolling reduction at 6 passes was ε_{h}=80%. The structure of the these materials was analyzed using scanning transmission electron microscope. The quantitative studies of the substructure was performed with MET-ILO software, on the basis of images acquired on scanning transmission electron microscope. Performed substructure investigations showed that using the rolling with the cyclic movement of the rolls method can refine the microstructure of these materials to the ultrafine scale.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 975-978
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of rolling with cyclic movement of rolls method on structure and hardness of CuCr0.6 alloy
Autorzy:
Rodak, K.
Urbańczyk-Gucwa, A.
Radwański, K.
Powiązania:
https://bibliotekanauki.pl/articles/1058106.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.F-
61.72.Ff
81.05.Bx
81.40.Rs
83.50.-v
Opis:
A novel severe plastic deformation method entitled rolling with cyclic movement of rolls was proposed to fabricate ultrafine grained CuCr0.6 copper alloy. The alloy in the solution treated conditions was processed by rolling with cyclic movement of rolls method by using process parameters as amplitude of rolls movement (A = 0.9 mm), frequency of rolls movement (f = 1 Hz), rolling reduction (ε_{h} = 50%) and rolling rate (v = 1, v = 2, v = 3 rpm). Light microscopy, scanning electron microscopy and a electron backscattering diffraction detector, and scanning transmission electron microscopy were used for microstructural characterization, and hardness tests for a preliminary assessment of mechanical properties. Quantitative studies of the average diameter of the subgrains d (μm) and the average diameter of the grains D (μm) were performed using the scanning electron microscopy/electron backscattering diffraction method. Misorientation angles were analyzed by the Kikuchi-line technique using TSL-OIM software. The results show that the samples underwent very high strain at the lateral areas and smaller at the central areas. As a result, the microstructure became heterogeneous and remained unchanged with change in compression rate. The transverse movement of rolls causes in the material significant effect of refining structure in peripheral areas of sample.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1151-1154
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controlling Mechanisms of Creep Deformation of New Air-Hardenable TiAl-Based Alloy
Autorzy:
Staneková, H.
Lapin, J.
Pelachová, T.
Powiązania:
https://bibliotekanauki.pl/articles/1418511.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
62.20.F-
62.40.+i
81.30.Mh
83.50.-v
Opis:
In the present work, controlling mechanisms of creep deformation of a new cast air-hardenable Ti-46Al-8Ta [at.%] alloy was studied. Long-term constant load tensile creep tests combined with an abrupt change of the applied stress were performed at 700°C. The response of the alloy to a stress reduction is analyzed. Transient behaviour with zero creep before recommencing creep at a reduced load is related to possible creep deformation mechanisms. The dislocation microstructures are analysed for creep strains corresponding to the minimum creep rate by transmission electron microscopy. The controlling mechanisms of creep deformation are identified from the transient creep behaviour of the alloy during stress reduction, the stress exponent and dislocation microstructures observed after creep testing.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 512-515
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Phase Decomposition on Magnetic Structure of $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ Alloy
Autorzy:
Świderska, K.
Jankowska-Kisielińska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1385743.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
64.75.-g
75.40.-s
75.47.Np
75.50.Ee
81.40.Rs
Opis:
The purpose of present investigation was to study the effects of phase decomposition of the $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ alloy on its magnetic ordering. The single-crystal sample was examined by elastic neutron scattering before and after five subsequent annealing runs. The results indicate that in small fraction of the quenched sample volume there are two types of antiferromagnetic order: one of them AF1 of the long range, the other one of the short range. Ageing induces phase decomposition which yields disappearance of AF1 long range order and increase of the volume of new ordered phase. The results of the investigations of the aged sample indicate that regions of new tetragonal phase exhibit antiferromagnetic ordering with magnetic moments of Mn atoms arranged as in the pure compound MnNi but with unequal domain distribution. The intensity of magnetic component of super-structure reflections increases with the duration of ageing at lower rate than component due to atomic order.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 394-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and Some Physical Properties of Chemically Deposited Nickel Sulfide Thin Films
Autorzy:
Hammad, A.
ElMandouh, Z.
Elmeleegi, H.
Powiązania:
https://bibliotekanauki.pl/articles/1400567.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cp
68.37.Hk
68.55.jd
68.55.J-
78.20.Ci
78.68.+m
73.50.Lw
73.90.+f
Opis:
$Ni_2S_{2-x}$ thin films with x=0, 0.5, and 1 were prepared by chemical bath deposition technique. Amorphous structure was discovered by XRD for x=1, while α-Ni₇S₆ and NiS phases were discovered for x=0, and x=0.5 respectively. SEM graphs of the studied films have confirmed the XRD results. Optical band gap values increase from 0.845 to 0.912 eV, with increase of the composition x from 0 to 1. Activation energy values increase in the range from x=0 to x=0.5 and does not change for x=1.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 901-903
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electroluminescence Investigation of the Lateral Field Distribution in AlGaN/GaN HEMTs for Power Applications
Autorzy:
Baeumler, M.
Polyakov, V.
Gütle, F.
Dammann, M.
Benkhelifa, F.
Waltereit, P.
Reiner, R.
Müller, S.
Wespel, M.
Quay, R.
Mikulla, M.
Wagner, J.
Ambacher, O.
Powiązania:
https://bibliotekanauki.pl/articles/1197910.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Fi
85.30.De
85.30.Tv
85.40.Bh
85.40.Qx
73.40.-c
73.90.+f
73.61.Ey
73.50.Mx
Opis:
The lifetime and stability of AlGaN/GaN heterostructure field effect transistors at high power levels can be enhanced by introducing field plates to reduce electric field peaks in the gate-drain region. Simulations of the electric field distribution along the channel using the 2D ATLAS software from Silvaco indicate that above a characteristic drain source voltage three spatially separated electric field peaks appear, one located at the drain-side edge of the gate foot, one at the end of the drain-sided gate field plate, and one at the end of the source shield field plate. The close correlation between lateral electric field and the electroluminescence due to hot electron related intra-band transitions can be very helpful when optimizing the electric field distribution in high power devices. Electroluminescence microscopy images of devices with gate and source shield field plate reveal the peaks located at the locations of enhanced electric field. By studying the voltage dependence of the electroluminescence peaks the influence of the field plates on the electric field distribution in source drain direction can be visualized.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 982-985
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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