Search results

1

Susceptibility of the Rare Earth Ternary RNiSi_{2} and RNiGe_{2} Compounds

100%

Gil A., Szytuła A., Tomkowicz Z., Wojciechowski K., Zygmunt A.

Acta Physica Polonica A

|

1994

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vol. 85

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issue 2

271-274

EN

The ternary silicides and germanides RNiX_{2} (R - rare earth, X = Si or Ge) with the orthorhombic CeNiSi_{2}-type structure are investigated by magnetometric measurements. CeNiSi_{2}, CeNiGe_{2} and SmNiGe_{2} have a nonmagnetic state in low temperatures. The compounds with R = Pr and Nd are ferromagnets while those containing R = Gd-Er are antiferromagnets. The de Gennes scaling of the Néel temperatures indicates a strong influence of the crystalline-electric field effects.

2

Influence of Pressure on Magnetization of (Cd_{1-x-y}Zn_{y}Mn_{x})_{3}As_{2}

100%

Bednarski H., Cisowski J., Lubczyński W., Voiron J., Portal J.

Acta Physica Polonica A

|

1995

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vol. 87

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issue 1

205-208

EN

The influence of hydrostatic pressure up to 0.6 GPa on magnetization of (Cd_{1-x-y}Zn_{y}Mn_{x})_{3}As_{2} with various compositions was studied at 4.2 K and in magnetic fields up to 7 T. The obtained experimental data were analysed within our generalized pair approximation model, treating the total Mn-Mn interaction strength as a sum of superexchange and the Bloembergen-Rowland exchange. As a result, we obtained satisfactory agreement between our approach and experiment by introducing a pressure dependence of p-d hybridization potential V_{pd} in the form V_{pd} ∝ d^{-4}, where d is the Mn-As bond length which decreases with pressure.

3

Magnetic Properties of Thorium Ferricyanide

100%

Göbl R., Zentková M., Kavečanský V., Kováč J., Zentko A.

Acta Physica Polonica A

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2000

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vol. 97

|

issue 5

835-838

EN

The magnetic properties of Th_{3}[Fe(CN)_{6}]·10H_{2}O were investigated. It was shown that this compound is antiferromagnetically ordered in the low temperature region. The observed antiferromagnetic ordering is stable only in the low field.

4

A Simple Localized-Itinerant Model for PrAl_{3}: Crystal Field and Exchange Effects

63%

Von Ranke P., Palermo L., Da Silva X.

Acta Physica Polonica A

|

1991

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vol. 80

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issue 4

583-590

EN

We present a simple magnetic model for PrAl_{3}. The effects of crystal field are treated using a reduced set of levels and the corresponding wave functions are extracted from the actual crystal field levels of Pr^{+3} in a hexagonal symmetry. The exchange between 4f- and conduction-electrons are dealt within a molecular field approximation. An analytical magnetic state equation is derived and the magnetic behaviour discussed. The parameters of the model are estimated from a fitting of the inverse susceptibility of PrAl_{3} given in the literature.

5

Theory of Strongly Correlated Systems in the Limit of Large On-Site Coulomb Repulsion

63%

Izyumov Y.

Acta Physica Polonica A

|

1994

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vol. 85

|

issue 1

103-115

EN

A strongly correlated electronic system is studied within the framework of the t-J model with the help of diagram technique for the Hubbard X-operators. The summing of some series of diagrams is suggested, corresponding to the following three types of approximations: the generalized random phase approximation, the mean field approximation, and the low density approximation. In generalized random phase approximation the dynamic magnetic susceptibility of paramagnetic phase is calculated, and boundaries of stability of this phase are found on the plane of Hamiltonian parameters and electron concentration n. It is shown that at some critical concentration n_{c} the system undergoes a crossover from the itinerant magnetism (n < n_{c}) to the magnetism with localized magnetic moments (n > n_{c}). Simultaneously, the system transfers from the Fermi-liquid behaviour to the regime of strong electron correlations with nonquasiparticle states. In mean field approximation equations for the order parameters were derived and phase transitions temperatures in a ferromagnetic and antiferromagnetic phases were obtained. In low density approximation a state of the saturated ferromagnetism was investigated and a critical concentration n_{s} was calculated when the nonsaturated ferromagnetism follows the saturated ferromagnetism.

6

EPR Spectra of Cr in CdTe Crystals

63%

Stefaniuk I., Bester M., Virt I., Kuzma M.

Acta Physica Polonica A

|

2005

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vol. 108

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issue 2

413-418

EN

The EPR studies of CdTe:Cr were performed on X-band (9.6 GHz) spectrometer at room temperature. Single CdTe crystals were doped by chromium Cr in the synthesis process. The spectra observed were resolved into two spectra. The first one consisted of very broad line (Δ B=100 mT) and the second one showed a typical fine structure. The complete angular dependence measurements were obtained. The fine structure of Cr^{2+} or Cr^{3+} ions was assumed and simulated. It follows from the theoretical analysis of the obtained spectra that degree of ionization of the chromium Cr dopant is 3+.

7

Magnetic Properties of Ho_{5}Ni_{2}In_{4}

63%

Tyvanchuk Y., Penc B., Szytuła A., Zarzycki A.

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issue 4

599-600

EN

X-ray diffraction and magnetic measurements of Ho_{5}Ni_{2}In_{4} are reported. This compound crystallizes in the orthorhombic Lu_{5}Ni_{2}In_{4}-type structure. Magnetic data indicate ferromagnetic properties below T_c = 30 K.

8

Magnetic Properties of DyTe

63%

Pokrzywnicki S., Duczmal M., Pawlak L., Nenkov K.

Acta Physica Polonica A

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1997

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vol. 92

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issue 2

351-354

EN

Dysprosium monotelluride is a metallic substance with one valence electron per formula unit belonging to the conduction band. It crystallizes in the defected NaCl-type structure (a= 0.6070 nm) with cation deficiency in the metal sublattice. AC and DC susceptibilities exhibit a maximum at 15 K and a second maximum at higher temperatures which position is field dependent.

9

Multiband s-f Model for Pseudobinary Intermetalic Gd(Al_{1-x}Me_{x})_{2} Alloys. II. Me=Pb, Bi, Si, Sb

63%

Matlak M., Zieliński J.

Acta Physica Polonica A

|

1991

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vol. 79

|

issue 5

717-719

EN

With the use of the formulae derived in the preceding paper we calculate the Curie temperature and the magnetic moment as functions of the concentration x for Gd(Al_{1-x}Me_{x})_{2} (Me = Pb, Bi, Si, Sb) alloys. The agreement with the recent experimental data is relatively good.

10

Magnetic Properties of (Cu_{x}Mn_{1-x})_3[Cr(CN)_6]_2·zH_2O Complexes

63%

Vavra M., Antoňák M., Jagličić Z., Mihalik M., Mihalik M., Csach K., Zentková M.

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issue 5

998-999

EN

Magnetization measurements were performed on the (Cu_{x}Mn_{1-x})_3[Cr(CN)_6]_2·zH_2O molecule-based magnets where x=0.0, 0.2, 0.25, 0.3, 0.35 0.4, 0.6, 0.8 and 1.0. Both the Curie temperature and saturated magnetization at first decrease with increasing value of x reaching the minimal value of T_{C} = 49.7 K and 0.17 μ_{B} for x=0.2 and then increase with substitution. The pronounced hysteretic behavior between zero-field cooled and field cooled regimes was observed for all samples. Magnetization changes the sign of magnetic polarization in zero-field cooled magnetization curve at the compensation temperature T_{comp} = 16 K for sample with x = 0.4. Our results indicate that the system behaves as mixed-ferri-ferromagnetic system.

11

Magnetic Properties of Layer-Type Compounds TlGdS_{2} and TlGdSe_{2}

63%

Duczmal M., Pawlak L., Pokrzywnicki S.

Acta Physica Polonica A

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2000

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vol. 97

|

issue 5

839-842

EN

Ternary thallium lanthanide dichalcogenides TlLnX_{2} (X = S, Se, or Te; Ln = lanthanide, except Ce and Pr) crystallize in the rhombohedral structure of α-NaFeO_{2} type ($R\overline{3}m$). Their crystal lattice consists of the layers of Ln^{3+} ions separated by three layers of the non-magnetic ions (-Ln-X-Tl-X-Ln-). The magnetization was measured in the field range 0-14 T. The molecular field constants λ_{m} were estimated by fitting the Brillouin function to the experimental magnetization plots. The difference between the λ_{m} values for the thallium gadolinium sulphide and the selenide corresponds to the different character of Gd-S and Gd-Se bonds and gives rise to the different J_{1} and J_{2} exchange integrals.

12

Geometrically Frustrated Kagome Lattice with Chemical Disorder

63%

Szymczak R., Baran M., Fink-Finowicki J., Krzymanska B., Aleshkevych P., Szymczak H.

|

EN

The effect of nonmagnetic Mg^{2+} and magnetic Co^{2+} doping in Kagome compounds was investigated using DC magnetic susceptibility. The main effect of doping is to change the crystal field parameters. It was shown that Co^{2+} doping increases considerably crystal field parameters in Ni_3V_2O_8 while doping with nonmagnetic Mg^{2+} ions decreases considerably crystal field parameters in Co_3V_2O_8 crystals.

13

Magnetic and Transport Properties of R_3Cu_3Sb_4 Compounds (R = La, Ce, Pr, Nd, and Sm)

51%

Skolozdra R., Baran M., Horyn A., Szewczyk A., Gorelenko Y., Szymczak H., Szymczak R.

Acta Physica Polonica A

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2002

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vol. 102

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issue 3

429-435

EN

Magnetic susceptibility, electrical resistivity, and thermopower of the series of the R_3Cu_3Sb_4 compounds (R=La-Sm) were measured over the temperature ranges 1.9-300 K (susceptibility and resistivity) and 80-370 K (thermopower). Below 25 K, resistivity of these compounds grows exponentially with decreasing temperature. For some compounds, R = Ce, Sm, a maximum on temperature dependence of resistivity is observed. Ce_3Cu_3Sb_4 compound undergoes a magnetic transition at 12 K.

14

Details of Magnetic Properties in Pb(Fe_{1/2}Nb_{1/2})O_{3}

51%

Maryško M., Laguta V., Raevski I.

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vol. 126

|

issue 1

376-377

EN

For Pb(Fe_{0.5}Nb_{0.5})O_{3} the χ(T) and m(H) measurements up to 70 kOe were performed with the aim to estimate the antiferromagnetic (AFM) and superantiferromagnetic (SAF) contribution to χ(T). Below T_{N} the increase of χ(T) is attributed to a small part of Fe^{3+} ions in the SAF clusters. For high fields the suppression of the AFM and enhancement of the SAF susceptibility was observed. An inflection point of the m(H) curves below the Néel point suggests the presence of a spin reorientation process connected with the AFM phase.

15

Magnetic Study of the Fe Coated by Au Nanoparticles

51%

Zeleňáková A., Kováč J., Kavečanský V., Zeleňák V.

Acta Physica Polonica A

|

2008

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vol. 113

|

issue 1

533-536

EN

Nanosized iron-gold magnetic nanoparticles with an average particle size 10 nm were prepared by a reverse micelle method. The magnetic properties measurements of DC and AC magnetization confirm behaviour typical of a superparamagnetic system, such as the irreversibility of the zero-field-cooled and field-cooled curves, the frequency dependence of a blocking temperature T_B, and revealing of coercivity H_C below blocking temperature. The quantitative analysis of AC susceptibility due to value of parameter C_1 = ΔT_B/(T_B Δ log f)=0.0242 confirming the existence of inter-particle interaction in our system.

16

Structural and Magnetic Properties of Dy(Fe,V,Si)_{12} Compounds

51%

Drzazga Z., Winiarska A., Chrobak A., Kaczorowski D.

Acta Physica Polonica A

|

1997

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vol. 92

|

issue 2

335-339

EN

An influence of Si on the structural and magnetic properties of Dy(Fe,V,Si)_{12} compounds is studied. X-ray diffraction shows that these materials crystallise in the tetragonal ThMn_{12}-type structure. An increase in the saturation magnetization, the Curie temperatures and magnetocrystalline anisotropy in the Si substitutional systems is observed when compared with DyFe_{12-x}V_{x}. The magnetic properties depend on the preferential site occupation and concentration of Si and V atoms in these compounds.

17

The J₁-J₂ Model on the Anisotropic Triangular and the Square Lattice: Similarities and Differences

51%

Schmidt B., Thalmeier P.

Acta Physica Polonica A

|

2015

|

vol. 127

|

issue 2

324-326

EN

The Heisenberg model on a triangular lattice is a prime example for a geometrically frustrated spin system. However most experimentally accessible compounds have spatially anisotropic exchange interactions. As a function of this anisotropy, ground states with different magnetic properties can be realized. On the other hand, the J₁-J₂ model on the square lattice is a well-known example for frustration induced by competing exchange. The classical phase diagrams of the two models are related in a broad range of the control parameter ϕ=^{-1}(J₂/J₁). In both cases three different types of ground states are realized, each model having a ferromagnetic and an antiferromagnetic region in the phase diagram, and a third phase with columnar magnetic order for the square lattice and an in general incommensurate spiral structure for the triangular lattice. Quantum effects lift degeneracies in the non-FM phases and lead to additional nonmagnetic regions in the phase diagrams. The contribution of zero point fluctuations to ground state energy, wave vector, and ordered moment is discussed.

18

Paramagnetism of Cu_3RE_2W_4O_{18} Semiconductors (RE = Gd, Dy-Er)

51%

Groń T., Tomaszewicz E., Duda H., Mazur S.

Acta Physica Polonica A

|

2013

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vol. 124

|

issue 5

885-887

EN

Cu_3RE_2W_4O_{18} tungstates (RE = Gd, Dy-Er) are paramagnets in the temperature range 4.2-300 K visible also in the absence of the energy losses in the curve of the imaginary part of magnetic susceptibility, χ". The negative values of the paramagnetic Curie-Weiss temperature, θ, may suggest the weak antiferromagnetic coupling below 4.2 K. The temperature independent component of magnetic susceptibility has a positive value indicating a domination of the Van Vleck contribution. Calculations of the effective number of the Bohr magnetons revealed that the orbital contribution to the magnetic moment comes mainly from the RE^{3+} ions.

19

The Symmetry and Optical Phenomena

51%

Malinowski S.

Acta Physica Polonica A

|

1991

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vol. 79

|

issue 4

565-589

EN

The explicit forms of the broken (by a electric field E, magnetic field H and spatial dispersion of wave vector k) point symmetry groups of a crystal are given. For these groups the dielectric permeability tensors: ε_{ij}(ω, E), ε_{ij}(ω, H) and ε_{ij}(ω, k) - the particular cases of ε_{ij}(ω, E, H, k) - are written out (the susceptibility tensors χ_{ij}(ω, E), χ_{ij}(ω, H) and χ_{ij}(ω, k) take the same forms). In order to illustrate the results obtained the electrooptical phenomena (connected with the tensors ε_{ij}(ω, E)) are discussed.

20

Dynamic Susceptibility in Thin Films with Antiferromagnetic Coupling between Layers

51%

Świrkowicz R.

Acta Physica Polonica A

|

1996

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vol. 90

|

issue 6

1215-1226

EN

The dynamic susceptibility of the system with antiferromagnetic coupling between layers is investigated within the framework of the multiband model using the equation of motion with random phase approximation. Calculations are performed in the mixed Bloch-Wannier representation and a general form for χ is found. The susceptibility can be written in terms of two-particle Green's functions expressed in the local coordinate system with the z axis aligned along the local magnetization. The expression depends on an angle between the magnetization direction in a given layer and the crystal axis. Preliminary numerical calculations are performed for two systems: ultrathin Cr film and Fe/Cr multilayer structure. Imaginary part of the susceptibility corresponding to different layers is calculated and spin waves are discussed.

Refine search results

Susceptibility of the Rare Earth Ternary RNiSi_{2} and RNiGe_{2} Compounds

Influence of Pressure on Magnetization of (Cd_{1-x-y}Zn_{y}Mn_{x})_{3}As_{2}

Magnetic Properties of Thorium Ferricyanide

A Simple Localized-Itinerant Model for PrAl_{3}: Crystal Field and Exchange Effects

Theory of Strongly Correlated Systems in the Limit of Large On-Site Coulomb Repulsion

EPR Spectra of Cr in CdTe Crystals

Magnetic Properties of Ho_{5}Ni_{2}In_{4}

Magnetic Properties of DyTe

Multiband s-f Model for Pseudobinary Intermetalic Gd(Al_{1-x}Me_{x})_{2} Alloys. II. Me=Pb, Bi, Si, Sb

Magnetic Properties of (Cu_{x}Mn_{1-x})_3[Cr(CN)_6]_2·zH_2O Complexes

Magnetic Properties of Layer-Type Compounds TlGdS_{2} and TlGdSe_{2}

Geometrically Frustrated Kagome Lattice with Chemical Disorder

Magnetic and Transport Properties of R_3Cu_3Sb_4 Compounds (R = La, Ce, Pr, Nd, and Sm)

Details of Magnetic Properties in Pb(Fe_{1/2}Nb_{1/2})O_{3}

Magnetic Study of the Fe Coated by Au Nanoparticles

Structural and Magnetic Properties of Dy(Fe,V,Si)_{12} Compounds

The J₁-J₂ Model on the Anisotropic Triangular and the Square Lattice: Similarities and Differences

Paramagnetism of Cu_3RE_2W_4O_{18} Semiconductors (RE = Gd, Dy-Er)

The Symmetry and Optical Phenomena

Dynamic Susceptibility in Thin Films with Antiferromagnetic Coupling between Layers