2016 IEEE Magnetic Society Distinguished Lecture
 
Low-resistance magnetoresistive devices using new materials
 
Prof. K. Hono

Research Center for Magnetic and Spintronic Materials,
National Institute for Materials Science (NIMS), Tsukuba, Japan


Magnetoresistive (MR) devices with low resistance-area product (RA) and high MR ratio are required for read sensors of high density hard disk drives (HDDs), high capacity STT-MARMs and other sensor applications. Here we review our recent activities on structure-property relationships of magnetic tunneling junctions (MTJ) and current-perpendicular-to-plane giant magnetoresistive (CPP-GMR) devices using combinations of new ferromagnetic (FM) and non-magnetic (NM) materials. For FM materials, we explored several Heusler alloys with high spin polarization. For NM materials, we explored new tunnel barriers that have excellent lattice matching with FM electrodes and new spacer materials with good band matching with FM layers. We also explored some oxide and compound semiconductors. To extract the highest MR outputs that can be expected from the intrinsic properties of the FM/NM combinations, optimization of the device structure is essential. Using an aberration corrected STEM, we characterized the interface structures of layered devices with a near-atomic resolution, by which we investigated the underlying mechanism for magnetic and transport properties of the MR devices.
 
Kazuhiro Hono received the BS and MS degrees in Materials Science from Tohoku University in 1982 and 1984, and a Ph.D. degree in Metals Science and Engineering from Penn State in 1988. After working as a post doc at Carnegie Mellon, he became a research associate at the Institute for Materials Research, Tohoku University in 1990. He moved to the National Institute for Materials Science (NIMS) as a senior researcher in 1995, and is now a NIMS Fellow and the Director of the Research Center for Magnetic and Spintronic Materials. He is also a professor in Materials Science and Engineering at the University of Tsukuba. His current research interest is materials science in magnetic and spintronics materials and their devices.