Spin polarized tunneling in III-V-based heterostructures with a ferromagnetic MnAs thin film and GaAs : MnAs nanoclusters

摘要

We have successfully fabricated epitaxial single-crystal magnetic tunnel junctions (MTJs) consisting of magnetic electrodes (ferromagnetic MnAs and GaAs:MnAs granular material) and a AlAs/GaAs III-V tunnel barrier, grown by molecular-beam epitaxy on GaAs(0 0 1) substrates. Clear tunneling magnetoresistance (TMR) was observed from 7 K up to room temperature. The bias voltage V-half at which the TMR ratio is reduced by half is 1200 mV at 7K, which is surprisingly high and much higher than that (similar to 40 mV) of ferromagnetic semiconductor-based MTJs. This result shows that GaAs:MnAs nanoclusters can be used as a spin injecting source in semiconductor-based spintronics devices. (c) 2006 Elsevier B.V. All rights reserved.