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Proceedings Paper

Dynamic detection of spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance (Conference Presentation)
Author(s): Paul A. Crowell; Changjiang Liu; Sahil Patel; Tim Peterson; Chad C. Geppert; Kevin Christie; Gordon Stecklein; Chris J. Palmstrøm

Paper Abstract

A distinguishing feature of spin accumulation in ferromagnet-semiconductor devices is its precession in a magnetic field. This is the basis for detection techniques such as the Hanle effect, but these approaches become ineffective as the spin lifetime in the semiconductor decreases. For this reason, no electrical Hanle measurement has been demonstrated in GaAs at room temperature. We show here that by forcing the magnetization in the ferromagnet to precess at resonance instead of relying only on the Larmor precession of the spin accumulation in the semiconductor, an electrically generated spin accumulation can be detected up to 300~K. The injection bias and temperature dependence of the measured spin signal agree with those obtained using traditional methods. We further show that this new approach enables a measurement of short spin lifetimes (< 100~psec), a regime that is not accessible in semiconductors using traditional Hanle techniques. The measurements were carried out on epitaxial Heusler alloy (Co2FeSi or Co2MnSi)/n-GaAs heterostructures. Lateral spin valve devices were fabricated by electron beam and photolithography. We compare measurements carried out by the new FMR-based technique with traditional non-local and three-terminal Hanle measurements. A full model appropriate for the measurements will be introduced, and a broader discussion in the context of spin pumping experimenments will be included in the talk. The new technique provides a simple and powerful means for detecting spin accumulation at high temperatures. Reference: C. Liu, S. J. Patel, T. A. Peterson, C. C. Geppert, K. D. Christie, C. J. Palmstrøm, and P. A. Crowell, “Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance,” Nature Communications 7, 10296 (2016). http://dx.doi.org/10.1038/ncomms10296

Paper Details

Date Published: 4 November 2016
PDF: 1 pages
Proc. SPIE 9931, Spintronics IX, 99310Z (4 November 2016); doi: 10.1117/12.2238669
Show Author Affiliations
Paul A. Crowell, Univ. of Minnesota Twin Cities (United States)
Changjiang Liu, Univ. of Minnesota Twin Cities (United States)
Sahil Patel, University of California at Santa Barbara (United States)
Tim Peterson, Univ. of Minnesota Twin Cities (United States)
Chad C. Geppert, Univ. of Minnesota Twin Cities (United States)
Kevin Christie, Univ. of Minnesota Twin Cities (United States)
Gordon Stecklein, Univ. of Minnesota Twin Cities (United States)
Chris J. Palmstrøm, Univ. of Minnesota Twin Cities (United States)
Univ. of California at Santa Barbara (United States)


Published in SPIE Proceedings Vol. 9931:
Spintronics IX
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

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