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Influence of CoO bond length on the spin state of Co in cobaltite perovskites RCoO 3 (R = Y, Ho)
Author(s) -
Zhu Zhili,
Gua Jinhua,
Jia Yu,
Hu Xing
Publication year - 2010
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200945426
Subject(s) - cobaltite , bond length , spin states , perovskite (structure) , condensed matter physics , ion , electronic structure , spin (aerodynamics) , chemistry , ab initio , materials science , crystallography , physics , crystal structure , thermodynamics , organic chemistry
A comparative study of the electronic structure and magnetic properties of YCoO 3 and HoCoO 3 has been carried out using ab initio density‐functional calculations with local spin density approximation (LSDA) and LSDA + U methods. It is found that YCoO 3 shows nonmagnetic (spin S = 0) insulator character below 600 K and an electronic transition of Co 3+ ions from a low‐spin (LS) state to a high‐spin (HS) state above 600 K. In contrast, HoCoO 3 shows nonmagnetic property with Co ions in a LS state over a wide temperature range (300–995 K). The intermediate‐spin (IS) state becomes more stable than the LS state only at a temperature of 1098 K in HoCoO 3 . We suggest that the variation of CoO bond length induced by the unit cell expansion may play an important role in the evolution of the spin state of Co 3+ with increasing temperature in these perovskite cobalt oxides. The discrepancy of the averaged CoO bond length in YCoO 3 and HoCoO 3 may be a likely reason for the difference of electronic properties between them. The decrease of the CoO bond length could result in stabilization of the LS state.