Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

/ V. I. Kuz'min [et al.] // Phys. Rev. B. - 2019. - Vol. 100, Is. 14. - Ст. 144429, DOI 10.1103/PhysRevB.100.144429. - Cited References:72. - The authors thank the Russian Scientific Foundation for the financial support under Grant No. 18-12-00022. . - ISSN 2469-9950. - ISSN 2469-9969РУБ Materials Science, Multidisciplinary + Physics, Applied + Physics,

Аннотация: To study non-Heisenberg effects in the vicinity of spin crossover in strongly correlated electron systems we derive an effective low-energy Hamiltonian for the two-band Kanamori model. It contains a Heisenberg high-spin term proportional to exchange constant as well as a low-spin term proportional to spin gap parameter epsilon(s). Using cluster mean field theory we obtain several non-Heisenberg effects. Near the critical value of spin gap epsilon(c)(s) there is a magnetic phase transition of first order. In the vicinity of epsilon(c)(s) in the paramagnetic phase we observe nontrivial behavior of the Curie constant in the paramagnetic susceptibility in the wide range of temperature. Reentrant temperature behavior of nearest-neighbor spin-spin correlations is observed at epsilon(s) epsilon(c)(s). Finally, the pressure-temperature magnetic phase diagram for ferroperriclase is obtained using the effective Hamiltonian.

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Держатели документа:
Fed Res Ctr KSC SB RAS, Kirensky Inst Phys, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Inst Engn Phys & Radio Elect, Krasnoyarsk 660041, Russia.
Fed Res Ctr KSC SB RAS, Sukhachov Inst Forest, Krasnoyarsk 660036, Russia.

Доп.точки доступа:
Kuz'min, V., I; Orlov, Yu S.; Zarubin, A. E.; Ovchinnikova, T. M.; Ovchinnikov, S. G.; Kuz'min, Valerii; Russian Scientific FoundationRussian Science Foundation (RSF) [18-12-00022]

/ V. A. Gavrichkov, Y. S. Orlov, T. M. Ovchinnikova, S. G. Ovchinnikov // Jetp Lett. - 2020. - Vol. 112, Is. 4. - P241-245, DOI 10.1134/S0021364020160055. - Cited References:34 . - ISSN 0021-3640. - ISSN 1090-6487РУБ Physics, Multidisciplinary

Аннотация: The effect of high pressure on the electronic characteristics of CoO is analyzed in the framework of the multielectron model of transition metal oxides. The specific features of spin crossover for d(7) terms of Co2+ are compared to those characteristic of d(5) and d(6) configurations. A pressure-induced transition between antiferromagnetic and ferromagnetic states at the spin crossover point is predicted. A model is proposed to describe the pressure-induced variation of the electrical resistance exhibiting a stepwise change by eight orders of magnitude at the structural transition point observed at 43 GPa and the subsequent metallization above 133 GPa.

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Держатели документа:
Russian Acad Sci, Siberian Branch, Fed Res Ctr KSC, Kirensky Inst Phys, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
Russian Acad Sci, Siberian Branch, Fed Res Ctr KSC, Sukachev Inst Forest, Krasnoyarsk 660036, Russia.

Доп.точки доступа:
Gavrichkov, V. A.; Orlov, Yu. S.; Ovchinnikova, T. M.; Ovchinnikov, S. G.