Gallium Iron room temperature Magnetoelectric Oxides

• Applicant: Professorin Dr. Marjana Lezaic
• Subject Area: Theoretical Chemistry: Molecules, Materials, Surfaces
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 208216925

Magnetoelectric (ME) materials, presenting a coupling between their magnetic and electric properties, allow the control of the magnetization of a material through an electric field. This opens perspectives towards a new type of non volatile memory with high endurance, low access time and low power consumption: magnetoelectric memories (MERAMs). Unfortunately, materials presenting a ME coupling are scarce. Those presenting this effect at room temperature and having a non zero magnetization, essential for the real development of the applications, are even scarcer.We propose to study the possibilities in terms of magnetoelectricity of a promising but still rather unknown material, especially in thin films: Ga2-xFexO3 (GFO). This material is pyroelectric, ferrimagnetic, and has one of the highest ME couplings observed for a single-phased material. It’s the first material observed to simultaneously present a strong ME coupling and a resulting magnetization. Its Curie temperature is above room temperature (370 K) for x=1.4. The origin of its electric and ME properties is however still unclear. Until recently, no sufficiently high crystalline quality thin films of this material could be made. This de facto annihilated its potential applications in electronic devices.This project proposes to take advantage of the ability recently acquired by one of the partners to deposit high quality GFO thin films. Its goal is to perform a complete theoretical and experimental study of GFO magnetoelectricity. The theoretical part will consist in first principles calculations aiming at determining the origin of the ME effect in GFO, with a view to find ways to increase it. Different dopings of the GFO structure will be considered, guided by the theoretical part. Consistency of the theoretical part will be evaluated a posteriori through comparison of its predictions with the ME effect experimental characterization of pure and doped GFO thin films.

• DFG Programme: Research Grants
• International Connection: France
• Participating Persons: Professor Dr. Brice Gautier; Professorin Dr. Nathalie Viart