Ferrimagnetism induced by thermal vibrations in oxygen-deficient manganite heterostructures

TL;DR

This paper proposes a novel defect-engineering method to induce ferrimagnetism in transition-metal oxides through temperature-dependent oxygen vacancy displacements, revealing a unique temperature-dependent magnetic behavior.

Contribution

It introduces a new mechanism for ferrimagnetism based on thermal vibrations and oxygen vacancies, supported by density functional theory calculations.

Findings

Ferrimagnetism can be induced by thermal vibrations in oxygen-deficient manganite heterostructures.

The mechanism is absent at 0K and strengthens with temperature before disappearing at high disorder.

The temperature dependence provides an experimentally detectable signature.

Abstract

Super-exchange most often leads to antiferromagnetim in transition-metal perovskite oxides, yet ferromagnetism or ferrimagnetism would be preferred for many applications, for example in data storage. While alloying, epitaxial strain and defects were shown to lead to ferromagnetism, engineering this magnetic order remains a challenge. We propose, based on density functional theory calculations, a novel route to defect-engineer ferrimagnetism, which is based on preferential displacements of oxygen vacancies due to finite temperature vibrations. This mechanism has an unusual temperature dependence, as it is absent at 0K, strengthens with increasing temperature before vanishing once oxygen vacancies disorder, giving it a unique experimentally detectable signature.