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. Flatte, P. M. Voyles, C. J. Palmstrom, P. A. Crowell

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We have measured the spin injection efficiency and spin lifetime in Co2FeSi/n-GaAs lateral nonlocal spin valves from 20 to 300 K. We observe large (∼40μV) spin valve signals at room temperature and injector currents of 103A/cm2, facilitated by fabricating spin valve separations smaller than the 1μm 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.

Original languageEnglish (US)
Article number235309
JournalPhysical Review B
Issue number23
StatePublished - Dec 30 2016

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation (NSF) under DMR-1104951, C-SPIN, one of the six centers of STARnet, an SRC program sponsored by MARCO and DARPA, the Materials Research Science and Engineering Centers (MRSEC) program of the NSF under DMR 08-19885 and DMR 14-20013, and the NSF NNCI program.

Publisher Copyright:
© 2016 American Physical Society.

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