Influence of spin transfer and contact resistance on measurement of the spin Hall effect

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Abstract
When a longitudinal spin-unpolarized charge current flows in a thin slab of nonmagnetic metal with strong spin-orbit coupling of conduction electrons, a transverse spin Hall voltage can be generated between both edges of the sample, and the spin Hall voltage can be detected by the measurement of an ordinary Hall voltage produced in a transverse metal strip which connects both edges of the sample. In this paper, we discuss the influences of spin transfer and contact resistances between the longitudinal sample and the transverse metal strip on the measurement of the spin Hall voltage. We show that, due to the spin transfer between the longitudinal sample and the transverse metal strip, the magnitude of the spin Hall voltage produced in the longitudinal sample and the magnitude of the ordinary Hall voltage produced in the transverse metal strip and the relation between them will all strongly depend on the contact resistances, thus in order to detect the spin Hall voltage correctly through the measurement of the ordinary Hall voltage, the influences of spin transfer and contact resistance need to be taken into account.