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Quasi-two-dimensional magnets with triangular motifs in the structure
Published in A.N. Vasiliev, O.S. Volkova, E.A. Zvereva, M.M. Markina, Low-Dimensional Magnetism, 2019
A.N. Vasiliev, O.S. Volkova, E.A. Zvereva, M.M. Markina
It was found that the magnetic order in A3Ga3Ge2BeO14 (A = Nd, Pr, Sm) is not established up to 500 mK. The χ−1(T) dependence deviates from the Curie–Weiss law at T < 50 K in the Pr composition, at T < 100 K in the Nd composition, and in the Sm composition does not obey this law in the entire temperature range. This behaviour is attributed to the van Vleck paramagnetism for rare-earth ions, caused by a change in the population of the sublevels of the main multiplet upon cooling [373]. The values of the Weiss paramagnetic temperature, estimated from the high-temperature region, are Θ = −38 K in Nd3Ga3Ge2BeO14 and Θ = −40 K in Pr3Ga3Ge2BeO14.
Electron states and bands in the cuprates
Published in J. R. Waldram, Superconductivity of Metals and Cuprates, 2017
In a Fermi liquid we expect to find Pauli paramagnetism with volume magnetic susceptibility χm=μeff2gF, so plots of (π2k2/3μB2)χm should be identical with plots of Sel/T in the normal state if g is constant, and should remain very similar if g varies with energy. Figure 13.6(c) shows that this prediction works very well over the whole of this doping range. (The argument ignores van Vleck paramagnetism and Landau and core diamagnetism, which it is thought should roughly cancel each other out, and assumes that that there is no substantial renormalization of the electronic magnetic moment.) This result suggests strongly that we are indeed dealing with a Fermi system, with the spin degrees of freedom attached to the individual fermions.
Diamagnetic and Paramagnetic Effects
Published in Daniel D. Pollock, PHYSICAL PROPERTIES of MATERIALS for ENGINEERS 2ND EDITION, 2020
Implicit in the foregoing are the ideas that the direction of the applied magnetic field is parallel to an axis of symmetry of an isotropic crystal in the field, because the theory is most applicable to monatomic gases. Where the crystal is real and anisotropic, or is composed of molecules, this may not necessarily be the case. When these factors must be considered, the susceptibility, as given by Equations 8-32, 8-32a, or 8-33, must be modified by the inclusion of an additional positive term that results from polarized dipole moments. This term is called the Van Vleck paramagnetism. The substance will either be dia- or paramagnetic, depending on the relative sizes of the two terms.
Thermodynamics of the bulk modulus of delta phase plutonium alloys
Published in Philosophical Magazine, 2019
Rajan also gives theoretical results for the magnetic susceptibility, and we attempted unsuccessfully to apply them to the available data [33,34]. The data show a large temperature-independent component, indicative of Van Vleck paramagnetism, and very little temperature dependence, which must include a sizeable contribution from magnetic impurities. It was not possible to find a sensible treatment of the Kondo susceptibility without knowing more about the impurity contribution.