Excess-Hole Induced High Temperature Polarized State and its Correlation with the Multiferroicity in Single Crystalline DyMnO3

TL;DR

This study reveals how excess holes in DyMnO3 induce a high-temperature polarized state that correlates with its low-temperature multiferroic behavior, offering a new way to tune multiferroicity.

Contribution

It demonstrates that excess holes creating Mn4+ ions induce a high-temperature polarized state, linking it to the material's multiferroic properties and providing a novel tuning method.

Findings

High-temperature polarized state forms above magnetic transition temperatures.

Excess holes lead to Mn4+ ions causing thermally stimulated depolarization.

The high-temperature polarization correlates with low-temperature ferroelectric order.

Abstract

Controlling the ferroelectricity and magnetism in multiferroic materials has been an important research topic. We report the formation of a highly polarized state in multiferroic DyMnO3 single crystals which develops well above the magnetic transition temperatures, and we attribute it the thermally stimulated depolarization current effect of excess holes forming Mn4+ ions in the system. We also show that this high temperature polarized state intimately correlates with the lower temperature ferroelectric state that is induced by the incommensurate spiral magnetic order of Mn spins. This study demonstrate an efficient approach to tune the multiferroicity in the manganite system.