Mechanical Signature of Heat Generated in a Current-Driven Ferromagnetic Resonance System

The spin-torque ferromagnetic resonance (ST-FMR) technique offers great potential for simplified measurement in rf spintronics. However, there has been little discussion of relevant heating effects due to dissipation from magnetization dynamics or anisotropic magnetoresistance. The authors show how to observe FMR heating through a sensitive mechanical thermometer. Monitoring magnetization dynamics independently via ST-FMR and this stress-induced mechanical resonance allows separation of any thermoelectric signal, and a refined outlook on thermal contributions to the spin Hall effect.