The role of impurities and oxygen vacancy of SrTiO3 perovskite oxide: Ab initio and 57Fe Mössbauer studies

A. M. MUDARRA NAVARRO; C. E. RODRÍGUEZ TORRES; L. A. ERRICO; K. NOMURA; T.TAKAHASHI

Cartagena

Conferencia; International Conference on the Applications of the Mössbauer Effect (ICAME 2023); 2023

Ab initiocalculations are performed using the full potential linearized extended planewave (FP-LAPW) method in the framework of density functional theory (DFT).  Considering different vacancyconcentrations and distributions in the host, we have investigated the effectsof oxygen vacancies on the magnetic and hyperfine properties and the magneticalignment of impurities, such as on SnO2 doped with Fe and Co.In this work, wepresent theoretical and experimental studies of the magnetic and hyperfineproperties of (Fe, Sn) co-doped perovskite oxide, SrTiO3.In our calculations, Fe and Sn impuritiespromote the creation of oxygen vacancies (preferably close to Fe atoms but farfrom Sn atoms), sharing oxygen vacancies with antiparallel spin orientation. Itwas predicted ab initio to form a ferrimagnetic entity, forming a pair ofmagnetic impurities. The calculations were then compared with the experimentalresults. SrTiO3 samples co-doped with 1.0% enriched 57Feand 0–10% Sn were obtained by sol-gel and pyrolysis. We compared the results ofMössbauer spectroscopy (MS) and sample magnetometry (VSM). We were able toidentify the hyperfine interactions observed by MS and unambiguouslycharacterize the local structure around the Fe atom. Finally, based ontheoretical results for the lowest energy Fe–Fe and Fe–Sn magneticconfigurations, the experimental behavior of saturation magnetization obtainedby VSM measurements can be understood and reproduced as a function of Snconcentration (similar to the magnetic moment per magnetic atom).