Magneto-Electric Voltage Due to Microwave Heating in CoFeB/Heavy Metal Bilayer System

The voltage change accompanying the magnetization reversal in a CoFeB/W bilayer system has been investigated. We find that the observed voltage shows a unique angular dependence and originates from the heat combined with the anomalous Nernst effect (ANE) and the inverse spin Hall effect (ISHE). From the analysis, Joule heating due to the high-frequency current in a Cu waveguide and the magnetization damping due to the precessional motion at off-resonant state are found to contribute to the heat source for the magneto-thermoelectric signal. The results observed in the CoFeB/Pt bilayer system also totally agree with the present scenario. This result provides an important aspect in future energy-harvesting devices based on spin.