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Tytuł:
Spin-Orbit Coupling for f-Electrons in a Crystalline Field
Autorzy:
Lulek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1929779.pdf
Data publikacji:
1993-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
Opis:
The notion of a spin-orbit interaction arises from consideration of dynamics of multielectron atoms, i.e. systems of N electrons in a spherical potential. This notion is essentially a single-particle one. We sketch its origin as a second-order correction when Dirac four-component wave equations for an electron in external electromagnetic fields are simplified to the two-component Pauli spinors. The constraints in spinorial degrees of freedom consist, roughly speaking, in neglecting the small component of the electron four-function. The spin-orbit interaction term serves to compensate effects of the small component. The crystalline field induces some deviations from spherical symmetry of an isolated atom, which yields some modifications of the spherical form of the spin-orbit interaction operator. These modifications can be described in terms of a number of tensor operators adapted to appropriate chains of subgroups of the spherical symmetry group. We present a classification of independent tensor operators and discuss the relevant parameters for f-ions.
Źródło:
Acta Physica Polonica A; 1993, 84, 5; 867-873
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rationalization of Spectra of Rare Earths in Condensed Matter
Autorzy:
Reisfeld, R.
Jørgensen, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/1929810.pdf
Data publikacji:
1993-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
Opis:
The parametrized models are compared with counter-intuitive consequences of the non-relativistic Schrödinger treatment. For both 4f$\text{}^{ q}$, 5f$\text{}^{ q}$ and d$\text{}^{9}$ systems in condensed matter, the energy levels must be strongly influenced by correlation effects. The parametrization of intensities is conceptually very different for f$\text{}^{ q}$ and d$\text{}^{9}$ compounds. The bandwidths of absorption and luminescence are discussed and related to the Born-Oppenheimer factorization.
Źródło:
Acta Physica Polonica A; 1993, 84, 5; 1011-1019
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocrystalline Anisotropy of Tb$\text{}_{1.1}$(FeCo)$\text{}_{11}$Ti
Autorzy:
Ivanova, T. I.
Pankratov, N. Yu.
Pastushenkov, Yu. G.
Skokov, K. P.
Powiązania:
https://bibliotekanauki.pl/articles/2013699.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ch
Opis:
The Tb$\text{}_{1.1}$Fe$\text{}_{11-x}$Co$\text{}_{x}$Ti (x = 0, 1, 2, 3, 4) compounds with the ThMn$\text{}_{12}$-type structure were studied by using the torque and magnetization measurements in order to investigate temperature and composition behavior of the magnetocrystalline anisotropy. The Tb$\text{}_{1.1}$(FeCo)$\text{}_{11}$Ti single crystals demonstrated spin reorientation transition from easy axis to easy plane with the decrease in temperature. The substitution of Co for Fe produces an enhancement of the Curie temperatures, decreases temperatures of spin reorientation transition and appearance of canted structure.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 847-850
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex Dielectric Coefficient of Breast Phantom Prepared for Breast Cancer Detection
Autorzy:
Sayinti, A.
Açikalin, E.
Çoban, K.
Vertii, A.
Powiązania:
https://bibliotekanauki.pl/articles/1400036.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.22.Ch
Opis:
Microwave measurement techniques attract attention due to its practical solutions in breast cancer imaging. Early detection of cancer is the purpose of these imaging studies. For these imaging processes, phantoms which reflect the properties of the area to be imaged are produced. The produced homogeneous phantoms are imaged by stepper frequency of radar technology, as the narrow bands are used for heterogeneous mixtures. Phantoms are used since 70's until today. Different methods are experimented for producing phantoms of tissue, muscle, fat, skin, etc. Iron powder, polymer materials, various oils and gelatins used today are the materials used for producing the phantoms. In this study, phantom breast imaging is aimed. Phantoms breast and breast tumor samples are created. For phantoms and tumor samples, reflection and transmittion measurements are done with Network Analyzer in X-Band (8.2-12.4 GHz). Complex permittivity is calculated with Agilent 85071 Material Measurement Software-Fast Method (NIST-iterative method). It was considered breast phantom with tumor model for 3D imagine at 2-3.5 GHz frequency range.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 464-466
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Properties of Triglycine Sulphate Crystals Admixtured with L-Threonine
Autorzy:
Czarnecka, A.
Stankowska, J.
Mielcarek, S.
Powiązania:
https://bibliotekanauki.pl/articles/1931325.pdf
Data publikacji:
1994-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.22.Ch
Opis:
The influence of L-threonine admixture on the dielectric properties of triglycine sulphate (TGS) crystals was studied. With increasing concentration of the admixture in the solution from which the crystals were grown, their maximum permittivity and spontaneous polarization were found to decrease, their Curie point was found not much different than that for pure TGS crystals (322 K), the coercive field and bias field increased. The domain structure of the obtained crystals was also studied by the liquid crystal method.
Źródło:
Acta Physica Polonica A; 1994, 85, 5; 849-858
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Dependence of Dielectric Properties of D-Serine Admixtured TGS Crystals on the Distance from the Seed of the Crystal Growth
Autorzy:
Stankowska, J.
Czarnecka, A.
Dongo Gemi, Bangobango
Powiązania:
https://bibliotekanauki.pl/articles/1929193.pdf
Data publikacji:
1993-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.22.Ch
Opis:
Dielectric properties of a D-serine admixtured triglycine sulphate (TGS) crystal were studied on samples cut out from different sites in the crystal. The value of spontaneous polarization P$\text{}_{s}$ measured on b-cuts was found to be independent of the site. Whereas the coercive field E$\text{}_{c}$ values were higher for the samples cut out closer to the seed than for those cut out at the ends of the crystal along b axis. After rejuvenation the values of the bias field E$\text{}_{b}$ increased in contrary to the effect observed in the pure TGS crystals. An exponentially decreasing dependence of the maximum permittivity ε$\text{}_{max}$ on the site of the samples (b-plates) cut out along b axis from -b to +b positions, was obtained.
Źródło:
Acta Physica Polonica A; 1993, 83, 4; 485-494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametrization of the Bilinear Orbit—Lattice Interaction
Autorzy:
Pastusiak, W.
Powiązania:
https://bibliotekanauki.pl/articles/1888013.pdf
Data publikacji:
1991-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
Opis:
A group theoretical parametrization scheme of the bilinear orbit-lattice interaction is presented. Using this scheme a general analytical form of this interaction in the point-charge electrostatic model has been obtained. Based on this general analytical form the second-order parameters of the bilinear orbit-lattice interaction have been calculated for a tetrahedral complex. For cubic complexes a microscopic interpretation of the G-tensor components in the long-wavelength approximation of acoustic waves is given for the first time. The presented scheme of parametrization as well as the method of calculations of the interaction parameters may be extended to other models of the crystal field.
Źródło:
Acta Physica Polonica A; 1991, 80, 1; 107-116
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Organometallic Complexes of f Elements. Are Molecular Orbital Calculations a Useful Tool for Spectroscopists?
Autorzy:
Jank, S.
Amberger, H.-D.
Powiązania:
https://bibliotekanauki.pl/articles/1945458.pdf
Data publikacji:
1996-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Sq
71.70.Ch
Opis:
The crystal field parameters of base-free (Me$\text{}_{3}$SiC$\text{}_{5}$H$\text{}_{4}$)$\text{}_{3}$Pr, (C$\text{}_{5}$H$\text{}_{5}$)$\text{}_{3}$Pr·NCCH$\text{}_{3}$, (C$\text{}_{5}$H$\text{}_{5}$)$\text{}_{3}$La(NCCH$\text{}_{3}$)$\text{}_{2}$:Pr, [Pr(C$\text{}_{8}$H$\text{}_{8}$)]$\text{}^{+}$ and Nd[N(SiMe$\text{}_{3}$)$\text{}_{2}$]$\text{}_{3}$ as model compound for Nd[CH(SiMe$\text{}_{3}$)$\text{}_{2}$]$\text{}_{3}$ were inserted into the corresponding energy matrices of a model spin-free f$\text{}^{1}$ system. Diagonalizing these matrices the crystal field splitting patterns of the f orbitals were calculated. These experimentally based molecular orbital schemes are compared with the results of previous model calculations.
Źródło:
Acta Physica Polonica A; 1996, 90, 1; 21-32
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Investigation by Scanning Tunnelling Microscopy in Liquid Medium
Autorzy:
Phaner, M.
Robach, Y.
de Villeneuve, C.
Wojczuk, S.
Olejniczak, W.
Porte, L.
Powiązania:
https://bibliotekanauki.pl/articles/1929313.pdf
Data publikacji:
1993-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ch
73.40.Gk
Opis:
Scanning tunneling microscopy in liquid environment has gained an increased interest in recent years. The specific features of the in situ observation of surface structures at the solid/liquid interface are first presented. Next, a high resolution imaging of high oriented pyrolytic graphite (HOPG) graphite surface shows the potentiality of our home-made microscope. The last study, performed on technological InP. substrates, illustrates the extensive applications of in situ imaging in the fields of semiconductor technology.
Źródło:
Acta Physica Polonica A; 1993, 83, 5; 611-619
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidation Studies of the Graphite Surface by Scanning Tunneling Microscopy and Photoelectron Spectroscopy
Autorzy:
Klusek, Z.
Phaner, M.
Krapf, P.
Porte, L.
Powiązania:
https://bibliotekanauki.pl/articles/1931811.pdf
Data publikacji:
1994-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ch
33.60.Fy
Opis:
Scanning tunneling microscopy and spectroscopy and X-ray photoelectron spectroscopy were used to study oxidation effects of nitric acid on highly oriented pyrolytic graphite surface. This treatment was performed at different temperatures and etching times with the aim of realizing local binding sites on the surface without creating deep defects. Then these three technics were found in good agreement to characterize the weakly oxidized surface. A wavy structure different from pure graphite at atomic scale was imaged by scanning tunneling microscopy. This modification was correlated to the presence of carboxylic groups on the surface revealed by X-ray photoelectron spectroscopy. Both spectroscopies of scanning tunneling and X-ray photoelectron demonstrated the vanishing of π bands characteristic from sp$\text{}^{2}$ graphitic hybridization. This was attributed to dehybridization corresponding to new bondings of the graphite carbons in the carboxylic groups.
Źródło:
Acta Physica Polonica A; 1994, 86, 6; 947-954
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Resonance and Dielectric Studies of a Nonlinear La$\text{}_{3}$Ga$\text{}_{5.5}$Ta$\text{}_{0.5}$O$\text{}_{14}$ Single Crystal Doped with Erbium
Autorzy:
Bodziony, T.
Typek, J.
Orlowski, M.
Majszczyk, J.
Wabia, M.
Berkowski, M.
Ryba-Romanowski, W.
Guskos, N.
Likodimos, V.
Anagnostakis, E. A.
Powiązania:
https://bibliotekanauki.pl/articles/2035732.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Kg
77.22.Ch
Opis:
Single crystal of erbium doped La$\text{}_{3}$Ga$\text{}_{5.5}$Ta$\text{}_{0.5}$O$\text{}_{14}$ grown by the Czochralski method have been investigated by electron paramagnetic resonance and dielectric spectroscopy methods. Dielectric permittivity ε measurements performed in 90-440 K temperature range have shown negligible dispersion for 1 kHz - 1 MHz frequencies and a Curie-Weiss type behaviour with C=47700 K andθ=-340 K. Electron paramagnetic resonance studies have revealed the presence of two different paramagnetic, monoclinic centres. The calculated g factor values are: g$\text{}_{1}$=1.449, g$\text{}_{2}$=11. 534, g$\text{}_{3}$=4.24 for the main M$\text{}_{1}$ centre and g$\text{}_{1}$=1.98, g$\text{}_{2}$=4.169, g$\text{}_{3}$=4.25 for the weaker M$\text{}_{2}$ centre. The temperature dependence of EPR line intensity for centre M$\text{}_{1}$ and M$\text{}_{2}$ is quite different - while lines attributed to M$\text{}_{1}$ could only be observed at low temperatures, below 20 K, lines of M$\text{}_{2}$ centre persisted up to 200 K. The M$\text{}_{1}$ centre is connected with Er$\text{}^{3+}$ ion entering substitutionally into La$\text{}^{3+}$ site, while M$\text{}_{2}$ is probably connected with 3d ions at the same site, unintentionally introduced into the material as an admixture.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 315-322
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of the Surface Energy for the Formation of the Domain Structure at Magnetoelastic Phase Transition
Autorzy:
Gomonaj, H. V.
Loktev, V. M.
Powiązania:
https://bibliotekanauki.pl/articles/2013067.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Ee
75.60.Ch
Opis:
The formation of the domain structure during magnetic ordering in the pure antiferromagnet with the rotational (non-180°) domains can be treated as thermodynamically preferable if the free energy of the sample is minimized with the account of surface energy. The analogy between the role of magnetostatic energy in ferromagnets and surface energy of antiferromagnet is traced. The behavior of the domain structure and macroscopic strain tensor in the external magnetic field is investigated.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 459-462
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Magnetic Ordering in NdAgAl₃
Autorzy:
Nallamuthu, S.
Džubinská, A.
Reiffers, M.
Nagalakshmi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1032835.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
65.40.Ba
Opis:
We present the detailed study of magnetic, thermodynamic, and transport properties of polycrystalline NdAgAl₃. The compound crystallizes in BaNiSn₃-type tetragonal structure with the space group I4mm. Magnetic, heat capacity and transport measurements indicate the possible antiferromagnetic nature of the ordering below 2 K. The compound shows the Schottky anomaly in heat capacity data. Magnetoresistance is negative at low temperature.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1015-1017
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Axial Dimension of Static Head-to-Head Domain Boundary in Amorphous Glass-Coated Microwire
Autorzy:
Kladivová, M.
Ziman, J.
Kecer, J.
Duranka, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030252.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Kj
75.60.Ch
Opis:
A new experiment allowing the study of static domain boundary dimensions in bistable microwire is proposed. In this experiment a static domain boundary is created by an inhomogeneous axial magnetic field. The changes in axial magnetic flux due to the presence of this boundary were measured along the microwire using two pick-up coils. Experimental results were compared with a simple theoretical model. For Fe_{77.5}Si_{7.5}B_{15} microwire with total diameter of 30 μm and metal nucleus diameter of 15 μm, good agreement between theoretical and experimental data was obtained for an axial dimension of the static domain boundary about 200 times larger than the diameter of the wire metallic core.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 639-641
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Theoretical Analysis of Zero Field Splitting of $Mn^{2+}$ in Ammonium Oxalate Monohydrate
Autorzy:
Kripal, R.
Pandey, S.
Powiązania:
https://bibliotekanauki.pl/articles/1535738.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
76.30.Fc
Opis:
The superposition model has been used to investigate the substitution of $Mn^{2+}$ in ammonium oxalate monohydrate. The zero field splitting parameters D and E calculated by the superposition model are compared with the experimental values $D_{exp}$ and $E_{exp}$, respectively, for $Mn^{2+}$ obtained by electron paramagnetic resonance. Both the zero field splitting parameters D and E calculated theoretically are in good agreement with the experimental values $D_{exp}$ and $E_{exp}$. The result indicates that the $Mn^{2+}$ ion substitutes for the $NH_4^{+}$ ion in ammonium oxalate monohydrate.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 629-632
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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