7月4日 University of California Davis分校刘凯教授学术报告：Magneto-Ionic Control of Metal/Oxide Interfaces and Magnetic Yoking Effects

报告题目：Magneto-Ionic Control of Metal/Oxide Interfaces and Magnetic Yoking Effects

时间：7月4日（周一）下午3:00

地点：唐仲英楼A213会议室

Magneto-Ionic Control of Metal/Oxide Interfaces and Magnetic Yoking Effects 
Kai Liu

Physics Department, University of California, Davis, CA 95616


The end of Moore’s law marks a new era in the high-technology industry and underscores the urgency of developing highly energy efficient nanoelectronics. Spintronics offers an exciting new paradigm to address this grand challenge. I will first discuss a promising route to achieving highly energy-efficient spintronic devices via magneto-ionic control of metal/oxide heterostructures. We have demonstrated effective magneto-ionic manipulation of GdFe/NiCoO interfaces due to a redox-driven oxygen migration, manifested through the interface-sensitive exchange bias effect [1]. We further show that the magnetoelectric coupling moderated by voltage-driven oxygen migration extends beyond the interface region in relatively thick AlO_x/GdO_x/Co(15 nm) films [2]. In the second part of my talk I will discuss an extremely sensitive magnetic yoking effect and tunable interactions in FePt based hard/soft bilayers mediated by the soft layer. Below the exchange length, a thin soft layer strongly exchange couples to the perpendicular moments of the hard layer; above the exchange length, just a few nanometers thicker, the soft layer moments turn in-plane and act to yoke the dipolar fields from the adjacent hard layer perpendicular domains. These findings demonstrate an effective yoking approach to design and control magnetic interactions in wide varieties of magnetic nanostructures and devices.

This work has been supported by the NSF (DMR-1008791, ECCS-1232275, and DMR-1543582), BaCaTec (A4 [2012-2]), and the France-Berkeley Fund.
1. D. A. Gilbert, et al, Nat. Commun. 7, 11050 (2016).
2. D. A. Gilbert, et al, Nat. Commun. in press; arXiv: 1605.07209.