Eur. Phys. J. B 48, 483-488 (2005)
https://doi.org/10.1140/epjb/e2006-00011-7

Theoretical study of anisotropy spin-orbit coupling and local lattice structure for Fe³⁺ ions in MgTiO₃:Fe³⁺ system^*

¹ Institute of Atomic and Molecular Physics, Department of physics, Sichuan University, Chengdu 610065, China
² International Centre for Materials Physics, Academia Sinica, Shengyang 110016, China
³ Institute of Applied Physics, Xihua University, Chengdu 610039, China

Corresponding author: ^a scu_kxy@163.com

Received: 29 June 2005
Revised: 28 November 2005
Published online: 19 January 2006

Abstract

The anisotropy spin-orbit coupling matrices for a d⁵ configuration ion in a trigonal ligand-field have been established. On basis of the anisotropy spin-orbit coupling matrices, the ground state zero-field splitting of the Fe³⁺ ions in ilmenite-structure MgTiO₃:Fe³⁺ system has been studied. The calculated results show that the anisotropy of Fe³⁺ ions in the diamagnetic ilmenite MgTiO₃ is important and the EPR parameters depend sensitively on the anisotropy divergent parameter. Moreover, the effect of the anisotropy divergent parameter on the second-order parameter D is obviously larger than that on the fourth-order parameter (a-F). Based on this point, the local lattice structure of Fe³⁺ ion in MgTiO₃:Fe³⁺ system is determined by diagonalizing the complete energy matrices for a d⁵ configuration ion in a trigonal ligand-field and considering the second-order as well as the fourth-order EPR parameters D and (a-F) simultaneously. Our results are consistent with the experimental proposal that Fe³⁺ ions may locate at both the Mg²⁺ and Ti⁴⁺ sites.