Magnetotransport and magnetization dynamics of GaMnAs thin films and magnetic tunnel junctions

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Abstract

We describe the comprehensive characterization of GaMnAs epitaxial thin films and magnetic tunnel junctions (MTJ) by complementary techniques ranging from high-resolution imaging to magnetometry, magnetotransport, time-resolved magneto-optics, and coplanar broadband ferromagnetic resonance (FMR). Magnetometry and magnetotransport on macroscopic samples allow deriving the saturation magnetization and quasi-static reversal fields. Perpendicular transport experiments on patterned MTJ pillars further reveal the tunneling magnetoresistance ratio. Additionally the precessional dynamics are characterized by time-resolved magneto-optics and broadband network analyzer FMR yielding the effective Gilbert damping and the sample anisotropies. The combination of the different techniques allows a comprehensive characterization of the key magnetostatic and dynamic material parameters of GaMnAs-based thin films and devices.

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