In this paper, a simple scheme related to the separation between the impurity and the neighbouring cation in MgTiO3 crystal is suggested in the case of charge misfitting substitution. According to the scheme, the impurity ion does not occupy the exact site of host ion, but is displaced along the C3 axis. The displacement direction depends upon the charge carried by the impurity. Based on this, two sites of the forms Cr(Mg)3+-Ti(Ti)4+ for Cr3+ (1) ion and Mg(Ti)2+-Cr(Mg)3+ for Cr3+ (2) ion in MgTiO3:Cr3+ crystals are proposed by comparing the EPR parameters between calculation and experiment.
部门归属
acad sinica,int ctr mat phys,shenyang 110015,peoples r china.;zheng, wc (reprint author), sichuan univ,dept mat sci,chengdu 610064,peoples r china
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