Micromagnetic Model Analysis of Spin-Transfer Torque Oscillator and Write Heads for Microwave-Assisted Magnetic Recording

Abstract

A micromagnetic model analysis was used to investigate spin-transfer torque oscillators (STOs) and magnetic write heads for microwave-assisted magnetic recording (MAMR). Our goal was to propose STOs, the Gilbert damping constant of the write head, and write head configurations that allow the STO element to operate at a low injected current density J. First, we derived the write head field and field generation layer rotations for various models with various main pole (MP) widths and MP throat heights. Second, we used the write head model and tried to reduce J by optimizing the Gilbert damping constant of the write head. Then, we used various STOs and write head structures and derived STO fields, clockwise and counterclockwise components, and FGL angles versus J. Finally, we performed media recording simulations and noted some challenges in the MAMR simulations.