Spin-transfer mechanism for magnon-drag thermopower

We point out a relation between the dissipative spin-transfer-torque parameter β and the contribution of magnon drag to the thermoelectric power in conducting ferromagnets. Using this result, we estimate β in iron at low temperatures, where magnon drag is believed to be the dominant contribution to the thermopower. Our results may be used to determine β from magnon-drag-thermopower experiments, or, conversely, to infer the strength of magnon drag via experiments on spin transfer