Showing papers on "Metamagnetism published in 1982"
TL;DR: In this article, the conditions for the metamagnetic transition between the paramagnetic and ferromagnetic states and between the weak ferromagnetworks between the normal and non-normal ferromagnets were derived in a simple model for an itinerant electron system.
Abstract: Rigorous conditions for the metamagnetic transitions between the paramagnetic and ferromagnetic states and between the weak ferromagnetic and normal ferromagnetic states are derived. The expressions for the conditions and the critical field are derived in the simple model for an itinerant electron system and for a combined system of localized magnetic moments and itinerant electrons. The results are applied to TiBe2, YCo2, Pd, compounds of rare earth metals and transition metals, Co(S, Se)2, etc. It is explained that TiBe2 and perhaps YCo2 and Pd will not show the metamagnetic transition in consistent with the experimental results.
140 citations
TL;DR: In this paper, magnetic susceptibilities and magnetization isotherms have been measured for a single crystal FeTiO 3, where the susceptibility parallcl to the c-axis has a large and sharp peak at T N = 580±03 K, while the perpendicular susceptibility is almost independent of temperature below T N .
Abstract: Magnetic susceptibilities and magnetization isotherms have been measured for single crystal FeTiO 3 The susceptibility parallcl to the c -axis has a large and sharp peak at T N =580±03 K, while the perpendicular susceptibility is almost independent of temperature below T N Magnetization isotherm at 42 K with fields applied along the c -axis exhibits a typical metamagnetic transition at H c =803±01 kOe, being the first observation of metamagnetism in 3 d transition metal oxides The transition is of the first order up to about 35 K, above which it is of the second order The experimental data are well reproduced by molecular field calculations with the best fit parameters of the anisotropy field H A =150 kOe, the ferromagnetic intrasublattice exchange interaction of 2 z 1 J 1 =285 K, and the antiferromagnetic intersublattice interaction of 2 z 2 J 2 =-667 K
56 citations
TL;DR: In this paper, a discussion of isotropic magnetic materials with localized magnetic moments between which the exchange interaction is more complex than in the usual Heisenberg model is presented, and experimental data on these materials and their theoretical interpretation are given.
Abstract: This review is primarily devoted to a discussion of isotropic magnetic materials with localized magnetic moments between which the exchange interaction is more complex than in the usual Heisenberg model. They include insulators for which the biquadratic or multispin exchange mechanisms are comparable with the bilinear exchange, conductors which do not satisfy the conditions of validity of the RKKY indirect exchange theory, and the nuclear magnetic material solid helium. Additionally, an analysis is made of high-anisotropy magnetic materials behaving similarly to isotropic non-Heisenberg materials. These anisotropic materials have anomalous properties, compared with the Heisenberg case. Experimental data on these materials and their theoretical interpretation are given. The following topics are discussed: 1) the conditions for a strong non-Heisenberg exchange and non-Heisenberg Hamiltonians; 2) quadrupole ordering and order-proper disorder phase transitions; 3) order-order and order-improper disorder phase transitions; 4) metamagnetism of isotropic materials; 5) normal sequences and "devil's ladders" of phase transitions between commensurable structures; 6) canted antiferromagnetism of high-symmetry crystals which do not obey the condition for the existence of relativistic Dzyaloshinskiĩ-type interactions.
48 citations
45 citations
TL;DR: In this paper, the transition from the antiferromagnetic structure to the ferromagnetic one, when the field is applied along c, occurs through an intermediate phase, which is very well accounted for using a simple Ising-like model which takes into account first and second nearest neighbours exchange interactions in the hexagonal layers.
40 citations
TL;DR: In this article, the magnetic properties of Y•M amorphous alloys (M = Fe, Co, Ni) in which only 3D magnetism is involved are described.
Abstract: In this paper we describe the magnetic properties of Y‐M amorphous alloys (M = Fe, Co, Ni) in which only 3d magnetism is involved. When the properties are not strongly dependent on environment effects, they are similar to those observed in the corresponding crystalline alloys: (i) Y‐Co and Y‐Ni alloys exhibit ferromagnetism when the 3d moment is large; (ii) far from the critical concentration for the disappearance of magnetism, the decrease of the 3d moment with increasing Y‐concentration is similar in amorphous and crystalline alloys; (iii) near the critical concentration, very weak itinerant ferromagnetism may be observed in amorphous Y‐Ni alloys as well as in the crystalline ones. On the contrary, the properties which are dependent on environment effects are strongly affected by the amorphous state: the properties of metamagnetism of itinerant electrons, which are very important in crystalline Y‐Co alloys near the critical concentration, lead in the amorphous state to a persistence of a mean 3d moment ...
28 citations
TL;DR: In this paper, the critical field for the metamagnetic transition, the critical temperature, and the temperature dependence of the magnetic susceptibility are qualitatively and semi-quantitatively explained consistently with the use of the model density of state derived from the recent band structure calculation by Asano.
Abstract: The metamagnetism in the ground state and magnetic susceptibilities of Co(S x Se 1- x ) 2 at finite temperature are discussed based on the recent spin fluctuation theory of Moriya-Takahashi. The critical field for the metamagnetic transition, the critical temperature, and the temperature dependence of the magnetic susceptibility are qualitatively and semi-quantitatively explained consistently with the use of the model density of state derived from the recent band structure calculation by Asano.
27 citations
TL;DR: In this article, the results of recent neutron scattering experiments in CeIn3 in the light of this expected behavior were discussed, and compared to the behavior of the more conventional cerium based metamagnet CeAl which was recently determined, as well as to the behaviour of other spin fluctuation magnets, such as CeAl2.
Abstract: In certain trivalent cerium compounds, fast spin fluctuations associated with the proximity of the 4f level to the Fermi level completely suppress magnetic order; in others the ground state is antiferromagnetic, but the spin fluctuations show up in thermodynamic and spectroscopic properties. These effects reflect the proximity in parameter space to a zero‐temperature magnetic/nonmagnetic transition. The critical behavior associated with this transition falls in the category of ’’quantum critical phenomena’’ and is expected to be quite interesting. This paper discusses the results of recent neutron scattering experiments in CeIn3 in the light of this expected behavior. Key features are nearly‐mean‐field behavior and strong suppression of the critical fluctuations. Comparisons will be made to the behavior of the more conventional cerium based metamagnet CeAl which we have recently determined, as well as to the behavior of other spin fluctuation magnets, such as CeAl2.
13 citations
TL;DR: In this paper, a new model of metamagnetic phase transition with temperature in Mn3GaC was proposed, which takes into account two independent strains (trigonal and isotropic ones) as functions of temperature, calculated similarly to the microscopic theory of magnetostriction.
Abstract: A new model of metamagnetic phase transition with temperature in Mn3GaC is proposed. The magnetoelastic Hamiltonian takes into account two independent strains (trigonal and isotropic ones) as functions of temperature, calculated similarly to the microscopic theory of magnetostriction. Necessary conditions for the transition are established within the molecular field approximation and the fit with experiment is discussed.
9 citations
TL;DR: In this article, it was shown that metamagnetic behavior of itinerant electrons can be described in the framework of the Fermi liquid model of spontaneous violation of reflectional symmetry.
1 citations
TL;DR: In this article, a general rule for any theory of spontaneous metamagnetism is derived and a new model with four-spin coupling and magnetostriction satisfies the new rule and describes well even the controversial metamagnetic transition in Mn 3 GaC.