Local Structure of Multiferroic TbMn2O5: Evidence for an Anomalous Terbium Oxygen Distribution

TL;DR

This study investigates the temperature-dependent local structure of TbMn2O5 using x-ray absorption spectroscopy, revealing an anomalous Tb-O distribution that correlates with magnetic and ferroelectric properties.

Contribution

It provides new insights into the local structural distortions and their relation to ferroelectricity in TbMn2O5, highlighting the role of Tb-O bond polarization.

Findings

Anomalous Tb-O distribution observed at various temperatures.

Distribution sharpens below Tb magnetic ordering temperature.

Distortions suggest rotations of MnOx polyhedra influence ferroelectricity.

Abstract

The temperature dependent local structure of TbMn2O5 was determined by x-ray absorption spectroscopy. An anomalous Tb-O distribution is found. At high temperature it is broad but resolves into two distinct peaks below approximately 180 K. The distributions sharpen below the Tb magnetic ordering temperature (approximately 10 K). The distortions in the Tb-O distribution, away from the Pbam structure, are consistent with rotations of the MnOx polyhedra about the c-axis and suggest that Tb-O bond polarization may play a significant role in the observed ferroelectric properties of this system.