Synthetic ferrimagnet nanowires with very low critical current density for coupled domain wall motion.

ABSTRACT: Domain walls in ferromagnetic nanowires are potential building-blocks of future technologies such as racetrack memories, in which data encoded in the domain walls are transported using spin-polarised currents. However, the development of energy-efficient devices has been hampered by the high current densities needed to initiate domain wall motion. We show here that a remarkable reduction in the critical current density can be achieved for in-plane magnetised coupled domain walls in CoFe/Ru/CoFe synthetic ferrimagnet tracks. The antiferromagnetic exchange coupling between the layers leads to simple Néel wall structures, imaged using photoemission electron and Lorentz transmission electron microscopy, with a width of only ~100?nm. The measured critical current density to set these walls in motion, detected using magnetotransport measurements, is 1.0?×?1011?Am-2, almost an order of magnitude lower than in a ferromagnetically coupled control sample. Theoretical modelling indicates that this is due to nonadiabatic driving of anisotropically coupled walls, a mechanism that can be used to design efficient domain-wall devices.

SUBMITTER: Lepadatu S 

PROVIDER: S-EPMC5431626 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature