Труды сотрудников института физики

/ S. G. Ovchinnikov, Y. S. Orlov // J. Exp. Theor. Phys. - 2007. - Vol. 104, Is. 3. - P. 436-444, DOI 10.1134/S1063776107030090. - Cited References: 24. - This work was supported by the program of the Division of Physical Sciences of the Russian Academy of Sciences “Strong Electronic Correlations,” the integration project SORAN-URORAN (grant no. 74), and the Krasnoyarsk krai Science Foundation . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The energies of terms with spins S = 0, 1, 2 have been found using exact diagonalization of the multielectron Hamlitonian of a multiband pd model for the CoO6 cluster. Co (e(g) orbital)-O hops, which form the covalent sigma bond, are shown to decrease the energy of the state (IS) with an intermediate spin (S = 1) as compared to the energy of the state (LS) with a low spin (S = 0). An analogue of the Tanabe-Sugano diagram that takes into account the covalence of the CoO6 cluster is constructed. The state with S = 1 is shown to be a ground state at certain model parameters. An increase in temperature is established to decrease the crystal field and, thus, favors the transition of the ground state from LS to IS at T = 100 K and the transition of the IS ground state to a state (HS) with a high spin (S = 2) at T = 550 K. The magnetic susceptibility of LaCoO3 is calculated with allowance for the LS, IS, and HS states and for the fact that the HS state exhibits threefold orbital degeneracy of the t(2g) shell, which results in an effective orbital moment L = 1 and the importance of spin-orbit interaction. The behavior of this magnetic susceptibility agrees well with the experimental chi(T) dependence of LaCoO3.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademogorodok, Krasnoyarsk, 660036, Russian Federation
Krasnoyarsk State University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Orlov, Yu. S.; Орлов, Юрий Сергеевич; Овчинников, Сергей Геннадьевич