Micromagnetic studies on switching dynamics of spin-torque oscillators

Spin-torque oscillator (STO) with reference layer (REF) has been proposed to be an efficient way to excite oscillation at low current density. A well-controlled STO is the center part of microwave assisted magnetic recording (MAMR); however, in the recording process, the STO is exposed in an alternative external head field in addition to the applied current. To assist the writing in MAMR, the STO should switch and change the oscillation chirality when the head pole flips, and the switching time needs to be shorter than 0.2 ns so as to follow the write field flipping. In this work, we would like to find the suitable design of Co/Pt REF to achieve this target.