Manipulating Multiple Order Parameters via Oxygen Vacancies: The case of Eu0.5Ba0.5TiO3-{\delta}

TL;DR

This study demonstrates a novel method to simultaneously manipulate magnetism and ferroelectricity in Eu0.5Ba0.5TiO3-{ extdelta} by controlling oxygen vacancies, revealing new pathways for multifunctional oxide materials.

Contribution

It introduces a mechanism where oxygen vacancies tune both magnetic and ferroelectric properties via defect states and ion displacement, a novel approach in transition metal oxides.

Findings

Oxygen vacancies create Ti3+ defect states mediating ferromagnetic coupling.

VO increase Ti off-center displacement, raising ferroelectric Curie temperature.

Potential for magnetoelectric coupling in Eu0.5Ba0.5TiO3-{ extdelta}.

Abstract

Controlling functionalities, such as magnetism or ferroelectricity, by means of oxygen vacancies (VO) is a key issue for the future development of transition metal oxides. Progress in this field is currently addressed through VO variations and their impact on mainly one order parameter. Here we reveal a new mechanism for tuning both magnetism and ferroelectricity simultaneously by using VO. Combined experimental and density-functional theory studies of Eu0.5Ba0.5TiO3-{\delta}, we demonstrate that oxygen vacancies create Ti3+ 3d1 defect states, mediating the ferromagnetic coupling between the localized Eu 4f7 spins, and increase an off-center displacement of Ti ions, enhancing the ferroelectric Curie temperature. The dual function of Ti sites also promises a magnetoelectric coupling in the Eu0.5Ba0.5TiO3-{\delta}.