Plentiful magnetic moments in oxygen deficient SrTiO3

TL;DR

This study uses correlated band theory to explore how oxygen vacancies and doping influence magnetism in SrTiO3, revealing that defect arrangements and charge states critically affect magnetic properties.

Contribution

It provides a detailed analysis of magnetic moments in oxygen-deficient SrTiO3, emphasizing the role of vacancy configurations and charge doping, which was less understood before.

Findings

Magnetism depends on vacancy arrangement and doping level.

Permanent magnetic moments can exist without doping electrons.

Charge state and defect geometry significantly influence magnetic behavior.

Abstract

Correlated band theory is employed to investigate the magnetic and electronic properties of different arrangements of oxygen di- and tri-vacancy clusters in SrTiO$_3$. Hole and electron doping of oxygen deficient SrTiO$_3$ yields various degrees of magnetization as a result of the interaction between localized magnetic moments at the defected sites. Different kinds of Ti atomic orbital hybridization are described as a function of the doping level and defect geometry. We find that magnetism in SrTiO$_{3-\delta}$ is sensitive to the arrangement of neighbouring vacancy sites, charge carrier density, and vacancy-vacancy interaction. Permanent magnetic moments in the absence of vacancy doping electrons are observed. Our description of the charged clusters of oxygen vacancies widens the previous descriptions of mono and multi-vacancies and points out the importance of the controled formation at the atomic level of defects for the realization of transition metal oxide based devices with a desirable magnetic performance.