185th Special MMU Seminar


Domain-wall physics in perpendicularly magnetized devices: some recent developments

Professor Henk J. M. Swagten
Department of Applied Physics
Eindhoven University of Technology
Date: Jun. 4 (Tue), 2013
Time: 10:30 - 12:00
Place: 8F middle seminar room, Sengen

In domain-wall (DW) devices with perpendicular magnetic anisotropy (PMA) using e.g. ultrathin Co, a number of exciting phenomena have been observed very recently with great promises for new solid-state memory devices, such as racetrack memory and magnetic random access memory (MRAM).

Ion irradiation with Ga and He is shown to be an effective tool to locally modify PMA properties, with which we could explore a kaleidoscope of new DW physics or device directions. For example, ion irradiation in PMA strips is used for (1) controlled pinning of DWs, (2) intrinsic DW resistivity as a function of the width of the DW, (3) a novel ratchet DW memory device by sawtooth shaping of the DW potential, and (4) Spin-Hall Effects (SHE) and Dzyaloshinskii-Moriya interactions dominating DW depinning as a new mechanism to drive magnetic domain walls along PMA strips.

In this talk, a selection of these exciting new developments using ion-beam irradiation will be highlighted along with other recent results. This includes electric-field control of PMA and DW motion, pinning DWs by magnetic nanopillars grown on top of an ultrathin magnetic strip, and the use of combined SHE and spin-transfer-torque to reduce the switching time and power consumption of novel MRAM.