Showing papers on "Curie–Weiss law published in 1983"
TL;DR: In this paper, the authors performed self-consistent KKR CPA calculations for the disordered local moment (DLM) state of Fe, Co, Ni and Cr at different temperatures.
Abstract: The authors perform self-consistent KKR CPA calculations for the disordered local moment (DLM) state of Fe, Co, Ni and Cr at different temperatures. The DLM state is a model for the metals above their Curie temperatures, in the paramagnetic state. They find the dependence of the local magnetic moment on temperature and determine the Stoner temperature. For Fe, they obtain the magnitude of the local moment above the Curie temperature to be about 85% of the ground-state value, whereas for Co and Ni it is about 50% of the ground-state value. For Cr they find that no self-consistent local magnetic moment exists in this DLM state. With slightly increased lattice spacing the sizes of the local moments are found to increase for both Fe and Ni.
162 citations
TL;DR: In this paper, the electronic structure of paramagnetic iron is calculated self-consistently within the local spin density functional formalism by applying the coherent potential approximation with the muffin-tin potential model.
Abstract: The electronic structure of paramagnetic iron is calculated self-consistently within the local spin density functional formalism by applying the coherent potential approximation with the muffin-tin potential model. The effective exchange parameters Jn are calculated as the interaction energy between two magnetic moments in the paramagnetic medium obtained. A discussion on the magnetism of iron above the Curie temperature is presented using the Heisenberg model with the calculated Jn.
147 citations
TL;DR: An intercalated 2H-type layer compound, Cr 1/3 NbS 2, was investigated by magnetic and neutron diffraction measurements as mentioned in this paper, and it was found that this compound is a helimagnet with a very long period along the c-axis and with the spins in the c -plane.
Abstract: An intercalated 2H-type layer compound, Cr 1/3 NbS 2 , was investigated by magnetic and neutron diffraction measurements. It was found that this compound is a helimagnet with a very long period along the c -axis and with the spins in the c -plane. The magnetic behavior is similar to that of an easy-plane type ferromagnet except for the magnetization curve in the c -plane. The Curie temperature is 127 K. The saturation magnetization corresponds to 2.9 µ B /Cr. The uniaxial anisotropy constant, K 1 , is -1.46×10 6 ergs/cc at 4.2 K. The magnetizatiom curve in the c -plane shows a metamagnetic behavior, the critical field of which is as low as 1.5 kOe except near T c . Small angle scattering measurements showed a helical structure with Q =0.013 A -1 (480 A period). The helical spin structure and the metamagnetism is explained as due to the antisymmetric exchange interaction.
143 citations
TL;DR: The magnetic behavior of eight samples of biotite and a lepidomelane was studied in the temperature range 15-300 K and analyzed in relation to their chemical composition as mentioned in this paper.
Abstract: The magnetic behavior of eight samples of biotite and a lepidomelane was studied in the temperature range 15–300 K and analyzed in relation to their chemical composition The platy morphology of biotite facilitates magnetic measurements with the applied field either in the plane of the sheets (Xe⊥ ) or perpendicular to the plane (Xe∥) At high temperature, the samples obey Curie‐Weiss laws, showing typical paramagnetic behavior which is due to the presence of both Fe2+ and Fe3+ ions However, the susceptibilities are anisotropic (χe⊥/χe∥≂125), because of a trigonal contribution to the crystal field which affects only the ferrous ions Formulae are given which permit the ferrous Curie‐Weiss parameters to be derived from the measured susceptibility At low temperature (T<10 K), three of the biotite samples containing high concentrations of iron (17 to 27 wt %) undergo an antiferromagnetic transition The magnetic structure consists of octahedral sheets of iron ions with their moments ferromagnetically co
69 citations
TL;DR: In this paper, a model based on the idea of localized magnetic moments is presented which allows to calculate the local magnetic moment expectation values of FeNi alloys, and the model allows the iron magnetic moments to orient parallel or antiparallel to the magnetization axis, depending on the local environment.
Abstract: A model based on the idea of localized magnetic moments is presented which allows to calculate the local magnetic moment expectation values of FeNi alloys. The only parameters of the model are the exchange integralsJ
FeFe,J
FeNi,J
NiNi. By assuming a “mixed” exchange interaction the concentration dependence of the exchange integralsJ
FeFe andJ
FeNi is calculated. The model allows the iron magnetic moments to orient parallel or antiparallel to the magnetization axis, depending on the local environment. It explains the magnetic abnormalies of FeNi Invar alloys as for example the concentration dependence of the mean magnetic moment and the Curie temperatures as well as the characteristic “flat” courves of the spontaneous magnetization.
48 citations
TL;DR: The magnetic susceptibility in the spin-glass concentration regime of amorphous alloys has been measured using a superconducting quantum interference detector magnetometer with an external field of 5 Oe for temperatures $5l~Tl~60.5$ K as discussed by the authors.
Abstract: The magnetic susceptibility in the spin-glass concentration regime of amorphous alloys ${({\mathrm{Fe}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x})}_{75}{\mathrm{P}}_{16}{\mathrm{B}}_{6}{\mathrm{Al}}_{3}$ with $x=0.04, 0.06, \mathrm{and} 0.08$ has been measured using a superconducting quantum interference detector magnetometer with an external field of 5 Oe for temperatures $5l~Tl~60.5$ K, and a Faraday balance with an external field of 5 kOe for $4.3l~Tl~300$ K. We observe a high-temperature ($Tg20{T}_{f}$) Curie-Weiss law with positive values for the paramagnetic Curie temperature, indicating predominantly ferromagnetic exchange couplings. At temperatures approaching the spin-glass freezing temperature, however, there are strong deviations from Curie-Weiss behavior. A simple theory is developed which allows a determination of the angular spin correlations in the spin-glass ground state from these deviations. The number of such correlated spins (1.5 to 4.4) determined from our data compares well with computer-simulation studies by Walker and Walstedt as well as data obtained by other authors for Au-Fe, Cu-Mn, and Co- and Mn-aluminosilicate spin-glasses.
40 citations
TL;DR: In this paper, the Curie-Weiss behavior has been shown for magnetic liquids containing cobalt particles diameter D vm = 27 A (sample A) and d vm = 96 A(sample B) for an internal field of 650 Oe and 100 Oe for samples A and B respectively, interpreted in terms of interparticle interactions.
40 citations
TL;DR: The magnetic properties of melt-spun iron-zirconium alloys are drastically altered by the addition of hydrogen as discussed by the authors, which increases both the Curie temperature and the moment per iron atom, from 252K and 1.6 mu B, respectively, to 382K and 2.0 mu B.
Abstract: The magnetic properties of melt-spun iron-zirconium alloys are drastically altered by the addition of hydrogen. The transformation of the magnetic order in Fe89Zr11 from collinear ferromagnetism to asperomagnetism below 60 K is suppressed in Fe89Zr11H20, which remains ferromagnetic at all temperatures. Hydrogenation increases both the Curie temperature and the moment per iron atom, from 252K and 1.6 mu B, respectively, to 382K and 2.0 mu B.
38 citations
TL;DR: In this article, the Curie-Weiss law was observed to be violated at high temperature dc-susceptibility data (up to 12 to 22 times the spin-freezing temperature To) in Ag Mn and Au Mn spinglasses.
25 citations
25 citations
TL;DR: In this paper, a simple derivation of parabolic 1/er-T curves is obtained by reconsidering the origin of the dielectric Curie-Weiss law, and the only assumption needed is the introduction of a non-linear temperature dependance of the macroscopic Dielectric polarization in the Clausius-Mossotti equation.
TL;DR: In this article, the effect of the biquadratic exchange interaction J′ on the Curie temperature has been calculated by the use of the Bethe-Peierls approximation and its effect is shown to be large for J′ > 0.
01 Jan 1983
TL;DR: In this paper, the magnetic properties of the C14 Laves phase Ti0.40Mn0.60 and the ρ and ϕ phase hydrides have been investigated.
Abstract: We have studied the magnetic properties of the C14 Laves phase Ti0.40Mn0.60 (homogeneity range from Ti0.33Mn0.67 to Ti0.45Mn0.55), of the p phase Ti0.46Mn0.54, and of the ϕ phase Ti0.48Mn0.52, as well as the magnetic properties of their hydrides. The investigation includes susceptibility measurements in the temperature range 5 to 360 K, magnetization measurements between 4.2 K and 250 K with fields up to 7.2 T, and Mossbauer effect measurements on 57Fe doped samples at 4.2 K and 295 K. Additionally, low temperature heat capacity measurements have been performed. While the Ti – Mn intermetallic C14, ρ and ϕ phases themselves are paramagnetic with susceptibilities independent of temperature, their hydrides are ferromagnetic with Curie temperatures of about 213 K, 87 and 155 K, respectively. The ρ and ϕ phase hydrides possess a weak itinerant ferromagnetism, whereas the ferromagnetism of the C14 Laves phase hydride is of a more localized type. The susceptibilities above Tc consist of Curie Weiss terms and large temperature independent contributions. The non-symmetric quadrupole split Mossbauer spectrum at room temperature indicates a distortion of a fraction of the tetrahedrons in the uncharged Ti0.40Mn0.60 Laves phase which is removed by hydrogenation. The onset of ferromagnetism in the Ti – Mn ternary hydrides is due to the volume expansion which causes a narrowing of the d bands and thus increases the density of states at the Fermi level upon hydrogenation.
TL;DR: In this article, an extensive domain of glasses is obtained in the ternary system of Mn2+ ions, where six hyperfine lines are centered at g = 2 with a hyperfine interaction constant A = 71.10−4 cm−1.
Abstract: An extensive domain of glasses is obtained in the ternary system. In the EPR spectra of Mn2+ ions, six hyperfine lines are centered at g = 2 with a hyperfine interaction constant A = 71.10−4 cm−1. The g = 4.3 line is observed, but is not well resolved. From the U.V. and visible spectra, the Mn has an octahedral coordination. The Raman bands are consistent with distorted and strongly bonded GeS4 tetrahedra. At low temperature, strong antiferromagnetic interactions are present in the glasses. For T > 60 K, the Curie Weiss law is verified, with δ = -76 K. The ac susceptibility exhibits a maximum at the freezing temperature.
TL;DR: The low temperature (1.3-20 K) heat capacity of the weak itinerant electron ferromagnet Sc3In was measured in magnetic fields up to 10 T.
TL;DR: The magnetisation of polycrystalline Er and alpha ErHx solid solutions (0
Abstract: The magnetisation of polycrystalline Er and alpha ErHx solid solutions (0
TL;DR: Magnetization measurements of magnetic semiconductor Sn1-xCrxTe (x <5 at%) crystals with the Curie temperature Tc = 150-300 K were made down to 2 K as mentioned in this paper.
TL;DR: A linear relationship was observed between the change in Curie temperature ΔT c and the field induced magnetic anisotropy K u of the amorphous alloy Fe 40 Bi 40 P 14 B 6, which strongly suggests that the microscopic processes which produce these changes are identical as discussed by the authors.
Abstract: A linear relationship was observed between the change in Curie temperature ΔT c and the field induced magnetic anisotropy K u of the amorphous alloy Fe 40 Bi 40 P 14 B 6 . The result strongly suggests that the microscopic processes which produce these changes are identical.
TL;DR: In this paper, the bulk amorphous alloys Sm4Co3, Gd4Co-3, and Er4Co 3 were investigated and their magnetic peculiarities were determined in the temperature range from 4.2 to 300 K.
Abstract: The bulk amorphous alloys Sm4Co3, Gd4Co3, and Er4Co3 are investigated. Their magnetic peculiarities are determined in the temperature range from 4.2 to 300 K. Paramagnetic Curie temperatures 110, 212, and 22 K are measured for Sm4Co3, Gd4Co3, and Er4Co3, respectively. The magnetic moments and the anisotropy energies are also derived.
[Russian Text Ignored].
TL;DR: In this paper, the hyperfine magnetic field at 181Ta in the ferromagnetic intermetallic Laves compound (Y0.97Hf0.03) was measured by the perturbed angular correlation method.
Abstract: The hyperfine magnetic field at 181Ta in the ferromagnetic intermetallic Laves compound (Y0.97Hf0.03) Fe2 is measured by the perturbed angular correlation method. A value Hhf(Ta) = –14.4 T is obtained at 300 K. The temperature dependence of this field, measured in the range from 78 K up to and above, the Curie point, is shown to be different from that of the bulk magnetization.
[Russion Text Ignored]
TL;DR: In this article, the authors measured the dielectric constant of magnetite as a function of applied magnetic field H appl at 5 K on three disk-shaped specimens having major surface parallel to (100), (110) and (111), respectively, in cubic notation.
01 Mar 1983
TL;DR: In this article, the magnetic properties of the spinel series Fe2.4, Fe 2.6, and Fe 3.1 were reported. Magnetic moment data were compared with theoretical values derived from different ion distribution models.
Abstract: Magnetic properties are reported for the spinel series Fe2.4—t
Cr0.6Ti
t
O4, 0≦t≦0.7, with t=0, 0.2, 0.4, 0.6 and Fe2.1—t
Cr0.9Ti
t
O4, 0≦t≦0.55, with t=0, 0.2, 0.4, 0.45, 0.5. Magnetic moment data are compared with theoretical values derived from different ion distribution models. With increasing Ti concentration the compositions become hard magnetic spinels due to the increased number of Fe2+ ions on A- and B-sites of the spinel lattice.
TL;DR: In this paper, the susceptibility of amorphous manganese aluminosilicate for frequencies from 0 to 25 MHz and in dc magnetic fields up to 1000 Oe was studied.
TL;DR: In this paper, the results of magnetic studies and electrical resistivity measurements on NiuCu1-u-xAlx solid solutions having u ≈ 0.77 and 0.87 magnetic moments at 4.2 K, as well as the Curie temperatures for both series of samples, decrease almost linearly by increasing the aluminium content.
TL;DR: In this paper, a mean field analysis of the magnetic transition of the reentrant compounds (Ho 0.6 Er 0.4 )Rh 4 B 4 and (Ho0.5 Lu 0.5 )Rh4 B 4 demonstrates that the specific heat, spontaneous magnetization and the depression of the Curie temperature due to the occurrence of superconductivity as observed in the above pseudoternary systems are quantitatively related.
TL;DR: In this article, the results of magnetic measurements performed on Ni08Cu02-xZnx alloys with x
Abstract: The authors report the results of magnetic measurements performed on Ni08Cu02-xZnx alloys with x