No abstract available

No abstract available

[en] A contribution to electrical resistivity and magnetoresistivity of Nd_2-xCe_xCuO₄ due to the exchange interaction between the conduction electrons and magnetic moments of Nd³⁺ ions has been calculated. The eigenstates of magnetic ions in the crystalline electric field of the compound have been taken from the neutron inelastic magnetic scattering experiments. The calculated temperature dependence of electrical resistivity proved to be nonlinear. Magnetoresistivity is negative at low temperatures for both H parallel c and H perpendicular to c. ((orig.))

[en] Magnetic susceptibility of the γ and α phases of metallic Ce has been calculated. Theoretical and experimental temperature dependences agree on the assumption that in the γ-phase the spin-orbit coupling exceeds crystal field effects significantly and in the α-phase the former and the latter are of the same order. The magnetic susceptibility of α-Ce was used to estimate the paramagnetic component of the inelastic neutron scattering spectrum. (author)

[en] Short note

[en] The results of the ²⁰⁹Bi NQR experiments carried out on α-Bi₂O₃, Bi₃O₄Br, Bi₂M₄O₉ (M=Al, Ga), Bi₂Ge₃O₉, and Bi₄Ge₃O₁₂ showed that these compounds are not diamagnets in the conventional sense. The Zeeman perturbed zero-field ²⁰⁹Bi NQR spectra gave an indication that local ordered magnetic fields of the order of 30-200 G exist in these substances comprising neither transition nor rare earth elements. Further aspects of this principally new phenomenon of yet unknown nature were studied by the ²⁰⁹Bi NQR experiments on the Bi₄Ge₃O₁₂ single crystal in external magnetic fields below 500 Oe, applied at various orientations with respect to the crystal axes. The spectral patterns of dramatically increased intensity and multiplicity, caused by the unknown magnetism of the compound, were observed in applied fields and modeled. Based on the results of the modeling, the conclusions were made that at least four magnetically non-equivalent Bi sites characterized by antiferromagnetically ordered local fields of the order of 30 G are present in the Bi₄Ge₃O₁₂ crystal; the intensity increase was interpreted to arise from the change in orientation of the electric field gradient axes at the Bi site upon applying an external magnetic field

[en] The contribution of the crystalline electric field (CEF) effects to the magnetic susceptibility of lanthanide cuprates Pr₂CuO₄ and ND₂CuO₄ have been investigated theoretically. The other sources of magnetic moments (paramagnetic Cu-ions, electrons of conductivity, excited multiplets of RE-ions) result in a contribution to the susceptibility which amounts only to about 1% of that of the CEF effects. Deviations from the Curie-Weiss law at low temperatures and the linear dependence of the reversed susceptibility χ_-1 on the temperature in the range 100-300 K (which have been found in experiments with polycrystalline samples of the compounds mentioned) can be explained by the peculiarities of the CEF level schemes of Pr³⁺ and Nd³⁺ ions. The anisotropy of the magnetic properties of Pr₂CuO₄ and Nd₂CuO₄ monocrystals is predicted as well as the antiferromagnetic character of the exchange interaction of RE-ions

[en] Short communication. 4 refs., 2 figs

[en] Short note. 7 refs

[en] The nuclear spin-lattice relaxation was studied in Bi₄Ge₃O₁₂ single crystal by ²⁰⁹Bi NQR. Experimental recovery curves for all ²⁰⁹Bi NQR transitions of nuclear spin I=((9)/(2)) in the temperature range 10-230 K were described by the single effective spin-lattice relaxation time T₁^*. The temperature dependence of 1/T₁^* was close to Tⁿ law with n=2.4-2.7. Theoretical treatment was given for the nuclear spin-lattice relaxation in the multi-level system for the case of single-axial crystalline electric field. Both quadrupole and magnetic mechanisms of relaxation were taken into account. It was shown that magnetic mechanism contributes noticeably to the spin-lattice relaxation in Bi₄Ge₃O₁₂ at T≤50 K