Square microwave-assisted magnetic recording at lower frequencies

Abstract

Microwave-assisted magnetic recording uses the transverse oscillating field at the level of Larmor frequency to record at substantially reduced write fields. However the ferromagnetic resonance frequency is proportional to media anisotropy and there is a limitation to generate such high frequency sinusoidal microwave fields. On the other hand, square microwave fields facilitate further reduction in write fields at much lower frequencies. As compared to sinusoidal microwave fields, the operating frequency regime of square microwave fields is broader in the presence of anisotropy distribution and less susceptible to variations in media parameters. These characteristics allow for the development of practical high anisotropic magnetic recording systems.