A radical approach to promote multiferroic coupling in double perovskites

TL;DR

This study explores how epitaxial thin films of double perovskites, specifically La2CoMnO6 and Bi2CoMnO6, can exhibit high-temperature ferromagnetism and multiferroic coupling, with properties tunable by strain and cation arrangement.

Contribution

The paper demonstrates a novel method to induce and control multiferroic coupling in double perovskite thin films through cation ordering and strain engineering.

Findings

La2CoMnO6 shows a Curie temperature of 250 K.

Bi2CoMnO6 exhibits ferromagnetism up to ~800 K.

Strain influences the magnetic transition temperature.

Abstract

Double perovskites provide a unique opportunity to induce and control multiferroic behaviors in oxide systems. The appealing possibility to design materials with a strong coupling between the magnetization and the polarization fields may be achieved in this family since these magnetic insulators can present structural self-ordering in the appropriate growth conditions. We have studied the functional properties of La2CoMnO6 and Bi2CoMnO6 epitaxial thin films grown by pulsed laser deposition. Cation-ordered La2CoMnO6 films display a magnetic Curie temperature of 250 K while cation-disordered Bi2CoMnO6 films present ferromagnetism up to ~ 800 K. Such high transition temperature for magnetic ordering can be further tuned by varying the strain in the films indicating an important contribution from the structural characteristics of the materials. Our approach might be generalized for other oxide systems. At this end, our results are compared with other multiferroic systems. The roles of various cations, their arrangements and structural effects are further discussed.