Modeling and Physics of Multiferroic Perovskite Manganites

TL;DR

This paper reviews the microscopic modeling of multiferroic perovskite manganites, focusing on their electronic and lattice structures, to understand their rich magnetoelectric phenomena and universal physics of multiferroicity.

Contribution

It presents a detailed theoretical model for RMnO3, elucidating the magnetoelectric phenomena and their underlying physics in multiferroic perovskite manganites.

Findings

Microscopic model explains magnetoelectric coupling in RMnO3

Theoretical insights clarify universal multiferroic physics

Understanding of spin-spiral multiferroics improved

Abstract

A new type of multiferroicity was experimentally discovered in 2003 in a perovskite manganite TbMnO$_3$ where its ferroelectricity is induced by cycloidally ordered Mn spins. Susequently, such spin-cycloid multiferroic phase was also discovered in $R$MnO$_3$ with other rare-earth ions $R$=Dy, Eu$_{1-x}$Y$_x$, Tb$_{1-x}$Gd$_x$, etc. In this class of materials, the magnetism and ferroelectricity are inseparably coupled, and resulting strong magnetoelectric coupling enables us to control/manipulate the electricity (magnetism) by magnetic (electric) fields. Moreover, many interesting magnetoelectric phenomena due to their cross correlation have been discovered. In this article, we discuss a microscopic theoretical model for $R$MnO$_3$ constructed by taking into account their precise electronic and lattice structures and overview the theoretical works based on this model which elucidated rich magnetoelectric phenomena of $R$MnO$_3$. The perovskite manganites are not only the first-discovered spin-spiral multiferroic materials but also a typical class of materials that exhibits most of the magnetoelectric phenomena manifested in many other multiferroics. Therefore, the comprehensive understanding of $R$MnO$_3$ directly leads to the clarification of universal physics of magnetoelectric phenomena in multiferroic materials.