APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011;
Dallas, Texas
Abstract: J15.00001 : Spin-Seebeck effect: Local nature of thermally induced spin currents in GaMnAs
11:15 AM–11:51 AM
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Author:
The spin-Seebeck effect refers to a spatial distribution of spins
in a
ferromagnetic material induced by a thermal gradient. This
macroscopic
spatial distribution of spins is several orders of magnitude
larger than the
spin diffusion length [1]. Here we describe measurements of the
spin-Seebeck
effect in the ferromagnetic semiconductor, GaMnAs [2]. The
thermally induced
spatial distribution of spins is inferred from the sign and
magnitude of the
inverse spin Hall voltage generated from local spin currents in
platinum
bars that are in electrical contact with the ferromagnetic
material. From an
experimental point of view, GaMnAs provides unique measurement
geometries
since the magnetic easy axes can be engineered in different
directions and
the low Curie temperature makes it convenient to perform
spin-Seebeck
measurements across the magnetic phase transition. Using different
experimental configurations we measure either the isolated
spin-Seebeck
signal, the planar and transverse Nernst effect, or a combination
of the
spin-Seebeck and Nernst effects. One of the most intriguing
aspects of the
spin-Seebeck effect is the observation that the spatial
distribution of
spins is maintained across electrical breaks revealing that the
effect does
not arise from a longitudinal spin current of charge carriers.
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[1] K.~Uchida, S.~Takahashi, K.~Harii, J.~Ieda, W.~Koshibae,
K.~Ando, S.~Maekawa, E.~Saitoh, \textit{Nature} \textbf{455}, 778
(2008).
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[2] C.~M. Jaworski, J.~Yang, S.~Mack, D.~D. Awschalom, J.~P.
Heremans, R.~C. Myers, \textit{Nature Materials} \textbf{9}, 898
(2010).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.J15.1