Longitudinal magnetothermopower in permalloy spin valves

We report measuring the longitudinal magnetothermopower (LMTP) and giant magnetoresistance (GMR) of Py/Cu/Py/FeMn spin valves grown on top of a thermally oxidized silicon substrate. These measurements showed that the LMTP behaves similarly to GMR, indicating a similar behavior of charge current and thermal current inside a spin valve. Since spin dependent interface scattering is the mechanism that governs GMR, these observations suggests that LMTP also originates from the spin dependent interface scattering of thermally induced current. However, there are differences between the LMTP and GMR signals, including a factor of two larger signal for the LMTP, that may indicate the LMTP is additionally sensitive to another scattering phenomenon in these heterostructures.