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]