resumo
We report magnetization measurements and magnetic resonance data for SrTiO3 doped by manganese. We show that the recently reported coexistent spin and dipole glass (multiglass) behaviours are strongly affected by the distribution of Mn ions between the Sr and Ti sites. Motivated by this finding we calculate the magnetic interactions between Mn impurities of different kinds. Both LSDA+U and many-body perturbation theory evidence that magnetic and magnetoelectric interactions are mediated by Mn-B(4+) ions substituting for Ti. We propose two microscopic magnetoelectric coupling mechanisms, which can be involved in all magnetoelectric systems based on incipient ferroelectrics. In the first one, the electric field modifies the spin susceptibility via spin-strain coupling of Mn-B(4+). The second mechanism concerns Mn pairs coupled by the position-dependent exchange interaction. Copyright (C) EPLA, 2010
palavras-chave
ELECTRONIC-STRUCTURE; RESONANCE; STRONTIUM; CERAMICS; SYSTEMS; SRTIO3
categoria
Physics
autores
Kuzian, RO; Laguta, VV; Dare, AM; Kondakova, IV; Marysko, M; Raymond, L; Garmash, EP; Pavlikov, VN; Tkach, A; Vilarinho, PM; Hayn, R
nossos autores
Oleksandr Tkach
Investigador Auxiliar
Paula Maria Lousada Silveirinha Vilarinho
Vice-Diretoragradecimentos
The authors thank M. D. GLINCHUK for fruitful discussions, they acknowledge the PICS program (Contracts CNRS No. 4767, NASU No. 267) and grant MSMT CR (Project No. 1M06002) for financial support and the IFW Dresden (Germany) which allowed them to use their computer facilities. The institutional research plan AVOZ10100521 is also acknowledged.