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 mechanism for tuning both magnetism and ferroelectricity simultaneously by using VO. Combining experimental and density-functional theory studies of Eu0.5Ba0.5TiO3-δ, 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-δ.
| Original language | English |
|---|---|
| Article number | 115105 |
| Journal | Physical Review B |
| Volume | 96 |
| Issue number | 11 |
| DOIs | |
| State | Published - Sep 6 2017 |
Funding
The authors thank Kelvin H. L. Zhang for valuable discussion, and also acknowledge the support of the National Basic Research Program of China (Grant No. 2014CB921001), the National Natural Science Foundation of China (Grants No. 11274237, No. U1632122, No. 11004145, No. 51202153, No. U1332209, No. U1435208, No. 11134012, No. 11174355, No. 11474349, and No. 11227405), and the Program for Postgraduates Research Innovation in University of Jiangsu Province under Grant No. CXZZ13_0798. The STEM studies (Q.H. and A.Y.B.) are supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. The TEM studies at Texas A&M University are funded by the US National Science Foundation (Grants No. DMR-1643911 and No. DMR-1565822). Ion beam analysis (Y.W.) and SHG measurements are supported by the Center for Integrated Nanothechnologies (CINT), a US DOE Nanoscale Research Center, jointly operated by Los Alamos and Sandia National Laboratories. A.R. gratefully acknowledges financial support from NSERC through a discovery grant, from FRQNT and from CFI through the Leaders Opportunity Fund.