Showing papers on "Curie–Weiss law published in 1967"
TL;DR: In this paper, an inequality relating binary correlation functions for an Ising model with purely ferromagnetic interactions is derived by elementary arguments and used to show that such a ferromagnet cannot exhibit a spontaneous magnetization at temperatures above the mean-field approximation to the Curie or critical point.
Abstract: An inequality relating binary correlation functions for an Ising model with purely ferromagnetic interactions is derived by elementary arguments and used to show that such a ferromagnet cannot exhibit a spontaneous magnetization at temperatures above the mean-field approximation to the Curie or “critical” point. (As a consequence, the corresponding “lattice gas” cannot undergo a first order phase transition in density (condensation) above this temperature.) The mean-field susceptibility in zero magnetic field at high temperatures is shown to be an upper bound for the exact result.
445 citations
TL;DR: The magnetization of ZrZn 2 has been measured as a function of magnetic field up to 48 kOe and of temperature from 2.0°K to 380°K as discussed by the authors.
Abstract: The magnetization of ZrZn 2 has been measured as a function of magnetic field up to 48 kOe and of temperature from 2.0°K to 380°K. The intrinsic magnetization extrapolated to 0°K increases strongly with external field. The magnetization at low field is found to vary as T 2 at low temperatures. The Curie temperature for a typical sample is 17.8°K, whereas the hysteresis loop is observed up to 30°K. A comment on the Curie temperature quoted in literatures has been made. The difference in magnetic properties among different samples has been noticed. The itinerant electron model of ferromagnetism can account for qualitatively the observed magnetic properties, whereas the localized-spin model proves inappropriate for this material.
95 citations
TL;DR: The magnetization-field-temperature characteristics of Cr${\mathrm{O}}_{2}$ and nickel just above their ferromagnetic Curie points, though quantitatively very different, are found to obey the same special type of equation of state, which is isomorphic with that recently proposed for the critical-point behavior of a fluid.
Abstract: The magnetization-field-temperature characteristics of Cr${\mathrm{O}}_{2}$ and nickel just above their ferromagnetic Curie points, though quantitatively very different, are found to obey the same special type of equation of state, which is isomorphic with that recently proposed for the critical-point behavior of a fluid.
63 citations
01 Jul 1967
TL;DR: In this paper, the high-temperature expansion for the specific heat of the Ising model of a ferromagnet (face-centred cubic lattice) was examined and it was concluded that the CH/R diverges at the Curie point as 1 09 (1 - Tc/T)-1/8 - 1 24 approximately.
Abstract: The high-temperature expansion for the specific heat of the Ising model of a ferromagnet (face-centred cubic lattice) is examined. It is concluded that the specific heat at constant field, CH/R, diverges at the Curie point as 1 09 (1 - Tc/T)-1/8 - 1 24 approximately. The critical energy of the face-centred cubic is estimated to be Uc/Uo = 0 2477 ± 0 0010 and the critical entropy Sc/R = 0 5901 ± 0 0010.
52 citations
TL;DR: In this article, the Curie temperature was found to increase nonlinearly from 36.0° to 84.5°K as x varies from 0 to 1.37 at which the F•AF transition temperature approaches 0°K.
Abstract: The distribution of magnetic ions and the crystallographic parameters remain essentially constant throughout the system Hg1−xCdxCr2S4. A study of the magnetic properties of this system was therefore undertaken in order to further elucidate the origin of the large difference in the magnetic properties already reported on the endpoints. The Curie temperature was found to increase nonlinearly from 36.0° to 84.5°K as x varies from 0 to 1. The low‐temperature F‐AF (ferromagnetic‐antiferromagnetic) transition and metamagnetism of HgCr2S4 penetrate well into the system, up to x≃0.37 at which the F‐AF transition temperature approaches 0°K.The distribution of magnetic ions remains constant, but the crystallographic parameters vary in the system Zn1−xCdxCr2Se4. Nevertheless, since ZnCr2Se4 is an antiferromagnetic with large positive θ, while CdCr2Se4 is a ferromagnet, a magnetic study of this system provides further evaluation of the theory of the ferromagnetic spinels. In addition, the evaluation of the nonlinear ...
35 citations
20 citations
TL;DR: In this article, a nickel single-crystal sphere is placed in an electromagnet with the field at right angles to the solenoid axis and along another 100 axis of the nickel crystal.
Abstract: A nickel single‐crystal sphere is placed in a solenoid with a 100 axis along the solenoid axis. The solenoid is placed in an electromagnet with the field at right angles to the solenoid axis and along another 100 axis of the nickel crystal. A detector coil is placed with its axis parallel to the solenoid in order to measure the change in the component of the magnetization of the sphere along the solenoid when the 20‐G field in the solenoid is reversed. This component is measured as a function of the transverse field of the electromagnet to obtain the effective susceptibility in applied fields from 20 to 5000 G. A sufficient time is allowed between each change of the electromagnet field for the large magnetocaloric effects to decay and the sample to return to the furnace temperature. The temperature dependence of the spontaneous magnetization in zero internal field and of the initial rate of increase with field of magnetization above the spontaneous magnetization below the Curie temperature, the temperature dependence of the initial susceptibility above the Curie temperature, and the field dependence of the magnetization at the Curie temperature and at a number of nearby temperatures are obtained. The single‐crystal results show sharper indications of the spontaneous magnetization than do identical measurements on polycrystalline Ni. The difference is attributed to Dzialoshinski interactions at grain boundaries. Analytic representations of some of the data are given.
19 citations
16 citations
15 citations
TL;DR: In this article, the observation of a magnetic susceptibility linearly dependent on magnetic field in antiferromagnetic DyFeO3 was reported and the symmetry of this effect and its temperature dependence were found to agree with theoretical predictions, based on crystallographic and magnetic data.
14 citations
TL;DR: In this article, the transmission of light through single crystals of EuO and EuS has been measured as a function of magnetic field, temperature, and wavelength, and it was shown that the intensity of light reaching the photodetector abruptly diminishes to nearly zero as the applied field is decreased below a critical field.
Abstract: The transmission of light through single crystals of EuO and EuS has been measured as a function of magnetic field, temperature, and wavelength. Below the Curie temperature, the intensity of light reaching the photodetector abruptly diminishes to nearly zero as the applied field is decreased below a critical field Hcrit. This effect is caused by diffraction of light by magnetic domains. Photographs of the spatial distribution of transmitted light for H
TL;DR: In this article, high field magnetization, Mossbauer and paramagnetic susceptibility data for Fe 2 TiO 4 are presented which can be explained in terms of an orbital contribution to the magnetic moment and anisotropy of the octahedral ferrous ion.
TL;DR: This article investigated the effect of magnetic ordering on the electrical resistivity of GdAl 2 and found a rather sharp break in the temperature dependence at a temperature about 25°K lower than the reported Curie temperature.
TL;DR: In this article, the magnetization and Curie temperature of a simple cubic ferromagnetic thin film were obtained using a Green function technique and Euler's summation method, respectively.
TL;DR: For a time independent Ising model, in the limit of a vanishing field, odd-order correlation functions are shown to be vanishing at all temperatures above the Curie temperature.
TL;DR: In this article, an explicit formula for the finite jump shown by the magnetic contribution to the specific heat at the Curie point in a ferrimagnetic substance with one kind of magnetic ions on two sublattices was derived.
TL;DR: In this paper, a correlation between the magnetic parameters and the density of electronic states as revealed by low-temperature specific heat measurements was found for Fe alloys with small amounts of Ti, V, Cr, Mn, Co, Ni, Al, Si, Mo, and W. The correlation with Curie temperature is significant.
Abstract: If itinerant electrons play an important role in ferromagnetism, one might expect some correlation between the magnetic parameters, e.g., the strength of the exchange interactions and the density of electronic states as revealed by low‐temperature specific heat measurements. Such a correlation is looked for in Fe alloys with small amounts of Ti, V, Cr, Mn, Co, Ni, Al, Si, Mo, and W. The quantity (1/γ)dγ/dc, where γ is the coefficient of the term in the specific heat which is linear in temperature and c is the solute concentration, is determined for these alloy systems. This quantity is compared with the similar derivatives for such quantities as spontaneous magnetization, Curie temperature, lattice parameter, and electrical resistivity. The correlation with Curie temperature is significant. Ti, V, Cr. W, and Co all raise the Curie temperature and depress the electronic specific heat, while Mn, Ni, Al, and Si lower the Curie temperature and increase the electronic specific heat. Mo is the exception produci...
TL;DR: It has been pointed out as discussed by the authors that near the Curie point and above it the length of the decay time of a fluctuation in the crystal lattice temperature of iron is close to the magnetic moment.
TL;DR: Hall effects and magnetic susceptibilities were measured on Cr1-xTe1+x(0≤x≤0.19) alloys between their Curie temperatures and about 350°C.
Abstract: Hall effects and magnetic susceptibilities were measured on Cr1-xTe1+x(0≤x≤0.19) alloys between their Curie temperatures and about 350°C. Ordinary Hall coefficient R0(positive) and extraordinary Hall coefficient R1(negative) are shown to be constant in this temperature region. Further, resistivity measurements reveal that these compounds are weakly temperature-dependent in resistivity with deflections at Curie points. Calculated Hall mobilities are 1.4×10-1 to 2.5 cm2/vsec. An estimated spin-orbit interaction field is consistent with 1.17×106 Oe of 3d electrons in optical spectroscopy.
TL;DR: In this paper, it was suggested that near or above the Curie point a thermodynamic fluctuation in magnetic moment is conditioned by a fluctuation of temperature in the corresponding region of the crystal lattice.