Tuning of dielectric properties and magnetism of SrTiO3 by site-specific doping of Mn

TL;DR

This study combines experiments and first principles calculations to show how site-specific Mn doping in SrTiO3 affects its dielectric and magnetic properties, revealing relaxor ferroelectric behavior and insights into magnetic states.

Contribution

It demonstrates the impact of Mn doping at different sites on dielectric and magnetic properties of SrTiO3, highlighting the role of off-centric displacement and relaxor behavior.

Findings

Phonon contributions to dielectric constant decrease with doping.

Large dielectric constant at high temperatures due to Mn at Sr site.

Evidence against a true multi-glass magnetic state.

Abstract

Combining experiments with first principles calculations, we show that site-specific doping of Mn into SrTiO3 has a decisive influence on the dielectric properties of these doped systems. We find that phonon contributions to the dielectric constant invariably decrease sharply on doping at any site. However, a sizable, random dipolar contribution only for Mn at the Sr site arises from a strong off-centric displacement of Mn in spite of Mn being in a non-d0 state; this leads to a large dielectric constant at higher temperatures and gives rise to a relaxor ferroelectric behavior at lower temperatures. We also investigate magnetic properties in detail and critically reevaluate the possibility of a true multi-glass state in such systems.