# Phase separation and ferroelectric ordering in charge frustrated LuFe2O4-x

## TL;DR

This study investigates charge ordering and phase separation in LuFe2O4-x, revealing two distinct charge modulations and their ferroelectric properties, influenced by oxygen content, through microscopy, structural analysis, and theoretical simulations.

## Contribution

It uncovers the coexistence of two charge-ordered phases with different modulations and demonstrates their ferroelectric ordering, highlighting the role of oxygen stoichiometry.

## Key findings

- Presence of two charge order ground states with distinct modulations.
- Incommensurate Q2 state is stable in oxygen-deficient samples.
- Both phases exhibit ferroelectric ordering as shown by simulations.

## Abstract

The transmission electron microscopy observations of the charge ordering (CO) which governs the electronic polarization in LuFe2O4-x clearly show the presence of a remarkable phase separation at low temperatures. Two CO ground states are found to adopt the charge modulations of Q1 = (1/3, 1/3, 0) and Q2 = (1/3 + y, 1/3 + y, 3/2), respectively. Our structural study demonstrates that the incommensurately Q2-modulated state is chiefly stable in samples with relatively lower oxygen contents. Data from theoretical simulations of the diffraction suggest that both Q1- and Q2-modulated phases have ferroelectric ordering. The effects of oxygen concentration on the phase separation and electric polarization in this layered system are discussed.

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Source: https://tomesphere.com/paper/0909.1613