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arXiv · 1610.03797

Spin injection and detection up to room temperature in Heusler~alloy/$n$-GaAs spin valves

T. A. Peterson·S. J. Patel·C. C. Geppert·K. D. Christie·A. Rath·D. Pennachio·M. E. Flatté·P. M. Voyles·C. J. Palmstrøm·P. A. Crowell
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Abstract

We have measured the spin injection efficiency and spin lifetime in Co$_2$FeSi/$n$-GaAs lateral nonlocal spin valves from 20 to 300 K. We observe large ($\sim$40 $μ$V) spin valve signals at room temperature and injector currents of $10^3~$A/cm$^2$, facilitated by fabricating spin valve separations smaller than the 1 $μ$m spin diffusion length and applying a forward bias to the detector contact. The spin transport parameters are measured by comparing the injector-detector contact separation dependence of the spin valve signal with a numerical model accounting for spin drift and diffusion. The apparent suppression of the spin injection efficiency at the lowest temperatures reflects a breakdown of the ordinary drift-diffusion model in the regime of large spin accumulation. A theoretical calculation of the D'yakonov-Perel spin lifetime agrees well with the measured $n$-GaAs spin lifetime over the entire temperature range.

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T. A. Peterson, S. J. Patel, C. C. Geppert, K. D. Christie, A. Rath, D. Pennachio, M. E. Flatté, P. M. Voyles, C. J. Palmstrøm, P. A. Crowell. 2016-10-12. Spin injection and detection up to room temperature in Heusler~alloy/$n$-GaAs spin valves. https://doi.org/10.1103/physrevb.94.235309

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