Nanomagnetic Playground: Magneto-Ionics and HAMR Media
The coming end of Moore’s law underscores the urgency of developing highly energy-efficient nanoelectronics. Spintronics offers an exciting new paradigm to address this grand challenge. In this talk I will first discuss magneto-ionic control of metal/oxide heterostructures, which offers a highly effective means to tailor material properties via modification of the interfacial characteristics. Currently, direct observation of ionic motion under buried interfaces and demonstration of its correlation with the physical properties have been challenging. Utilizing the strong oxygen affinity of gadolinium, we design a model system of GdFe/NiCoO bilayer films, where the oxygen migration is observed and manifested in a controlled positive exchange bias . In the second part I will discuss a magnetometry-based order parameter to characterize high anisotropy L10 FePt films  that are prototype media for the emerging heat-assisted magnetic recording (HAMR) technology. We also show an extremely sensitive magnetic yoking effect and tunable interactions in FePt based hard/soft bilayers mediated by the soft layer . These findings demonstrate an effective 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, APL Mater. 2, 086106 (2014).
3. D. A. Gilbert, et al, Sci. Rep. 6, 32842 (2016).
Hosted Ichiro Takeuchi.