Spin transfer torque dynamics in diluted ferromagnetic semiconductor nanostructures

• Applicant: Privatdozent Dr. Hans-Werner Schumacher
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 127855618

In this project the ultra fast spin transfer torque (STT) magnetization dynamics in GaMnAs diluted ferromagnetic semiconductor nanostructures are investigated. High density currents in GaMnAs based magnetic tunnel barrier (MTJ) nanopillars are used to induce STT magnetization precession. The precessional dynamics are detected by wide bandwidth time and frequency resolved measurements of the tunneling magneto resistance (TMR) of the nanopillars at cryogenic temperatures. The parameter dependence of the STT precession frequency and linewidth as function of external parameters (STT current density, static field angle and amplitude,…) will yield a detailed insight into the nature of STT in GaMnAs tunnel systems and will allow to distinguish possible vector components of STT. STT induced large angle precession will be studied by time resolved magneto transport. Based on this, optimized ultra fast STT magnetization reversal schemes will be devised and tested. This project will allow a deep insight into ultra fast STT magnetization dynamics and magnetization reversal of GaMnAs nanodevices. It thus provides the basis for the development of future ultra fast DMS based spintronic devices and applications.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1285: Semiconductor Spintronics
• Participating Person: Dr. Klaus Pierz