Perovskite Manganites Hosting Versatile Multiferroic Phases with Symmetric and Antisymmetric Exchange Strictions

TL;DR

This study maps the magnetoelectric phase diagrams of orthorhombic $R$MnO$_{3}$, revealing three multiferroic phases with distinct responses, and highlights the dominance of symmetric exchange in the $E$-type phase's polarization.

Contribution

It provides comprehensive phase diagrams and identifies the dominant exchange mechanisms in different multiferroic phases of $R$MnO$_{3}$, advancing understanding of magnetically induced multiferroics.

Findings

Three multiferroic ground states identified: $ab$-cycloidal, $bc$-cycloidal, and $E$-type phases.

The $E$-type phase exhibits polarization over 10 times larger than the $bc$-cycloidal phase.

Enhanced magnetoelectric response observed near phase boundary between different multiferroic phases.

Abstract

Complete magnetoelectric (ME) phase diagrams of orthorhombic $R$MnO$_{3}$ with and without magnetic moments on the $R$ ions have been established. Three kinds of multiferroic ground states, the $ab$-cycloidal, the $bc$-cycloidal, and the collinear $E$-type phases, have been identified by the distinct ME responses. The electric polarization of the $E$-type phase dominated by the symmetric spin exchange ($bm{S}_{i} cdot bm{S}_{j}$) is more than 10 times as large as that of the $bc$-cycloidal phase dominated by the antisymmetric one ($bm{S}_{i} times bm{S}_{j}$), and the ME response is enhanced near the bicritical phase boundary between these multiferroic phases of different origins. These findings will provide an important clue for the development of the magnetically induced multiferroics.