Origin(s) of symmetric background signal in Py SHE measurements

Ascertain whether any origin other than spin accumulation contributes to the symmetric background signal observed in Permalloy inverse spin Hall effect measurements in the H-shaped devices, and determine the extent to which spin accumulation alone accounts for the observed background.

Background

In measurements of the inverse spin Hall effect in Permalloy absorbers, a symmetric background signal appears that can be large relative to the SHE signal. The authors attribute this primarily to spin accumulation at the Cu/Py interface, but acknowledge that other mechanisms might also contribute. Establishing the complete set of contributing origins and quantifying their relative impact is necessary to isolate the intrinsic SHE response in these geometries.