Search

We review our recent achievements on optimization of spin injection from ferromagnetic into non-magnetic metals and characterization of spin transport properties in the non-magnetic nano-structures. We have realized the efficient spin injection by solving spin resistance mismatch problem in spin diffusion process across the interface between ferromagnetic and nonmagnetic metals. We analyzed temperature dependent spin relaxation length and time in Ag within the framework of the Elliot–Yafet mechanism based on spin–orbit interaction and momentum relaxation. The spin relaxation length in a light metal Mg is found comparable to that of Ag due to its peculiar electronic band structure in which so called spin-hotspots dramatically enhance spin relaxation. Spin relaxation properties in various metals are also quantitatively discussed. We employed commonly used Hanle effect measurements to characterize spin relaxation of spin current and reexamined both theoretically and experimentally the effect of spin absorption at the interface. The affected spatial profile of chemical potential due to the longitudinal and transverse spin absorption results in the broadened Hanle curve. All the Hanle curves both in metallic and semi-conductive materials including graphene fall into the universal scaling plot. Anatomy of spin injection properties of the junction and spin transport properties in non-magnetic metal is shown in tables. [ABSTRACT FROM AUTHOR]

The non-local spin injection in lateral spin valves is strongly expected to be an effective method to generate a pure spin current for potential spintronic application. However, the spin-valve voltage, which determines the magnitude of the spin current flowing into an additional ferromagnetic wire, is typically of the order of 1??V. Here we show that lateral spin valves with low-resistivity NiFe/MgO/Ag junctions enable efficient spin injection with high applied current density, which leads to the spin-valve voltage increasing 100-fold. Hanle effect measurements demonstrate a long-distance collective 2? spin precession along a 6-?m-long Ag wire. These results suggest a route to faster and manipulable spin transport for the development of pure spin-current-based memory, logic and sensing devices. [ABSTRACT FROM AUTHOR]