First principle prediction of vacancy-induced magnetism in non-magnetic perovskite SrTiO3

A theoretical study of magnetization in non-magnetic cubic perovskite SrTiO3 induced by vacancies in Sr, Ti and oxygen sublattices is presented using the full-potential linear augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA) for the exchange-correlation potential. The results show that the oxygen and titanium vacancies lead to the magnetization of non-magnetic perovskite SrTiO3 due to the spin-polarization of valence states for the Ti and O atoms, nearest to these vacancies. In result the insulating SrTiO3 becomes metallic-like with magnetic moments (per cell) 1.30 mu B and 3.54 mu B for non-stoichiometric SrTiO3-delta and SrTi1-delta O, respectively. On the contrary, our calculations reveal that for Sr vacancy the non-magnetic state of perovskite is retained, whereas the electronic spectrum of Sr1-delta TiO3 also adopts metallic-liketype. (C) 2007 Elsevier B.V. All rights reserved.