Voltage-Driven Magnetization Switching Controlled by Microwave Electric Field Pumping
Tatsuya Yamamoto, Takayuki Nozaki, Hiroshi Imamura, Shingo Tamaru, Kay Yakushiji, Hitoshi Kubota, Akio Fukushima, Shinji Yuasa
Abstract
We study the dynamic switching properties of a nanomagnet under microwave electric field pumping. The periodic modulation of an anisotropy field induced by microwave electric field pumping efficiently excites the uniform magnetization oscillation, allowing for precise control of magnetization switching. Accurate shaping of the pumping voltage waveform also enables us to investigate the transient reaction of magnetization to the relative phase difference of the pumping signal. We demonstrate both experimentally and theoretically the existence of a dead angle in which the uniform oscillation of magnetization is inhibited even though the microwave frequency itself satisfies the conditions of parametric excitation. Our results provide an energy-efficient way of manipulating ultrafast magnetization dynamics in nanomagnetic devices.