Magnetic properties and microstructure of TbCo/(SiN x/Co) n films

Abstract

The Tb 32Co 68/(SiN x /Co) n films ( n = 0 – 3) were prepared by magnetron sputtering. The magnetic anisotropy of all Tb 32Co 68/(SiN x /Co) n films are perpendicular to the film plane. It is found that the saturation magnetization ( M s) and perpendicular coercivity ( H c⊥) of the Tb 32Co 68/(SiN x /Co) 3 film are 263 emu/cm 3 and 3592 Oe, respectively. This film appears to be a promising material as a heat-assisted magnetic recording (HAMR) medium. The cross-sectional high resolution transmission electron microscope (HRTEM) images show that the interface roughness between the (SiN x /Co) n layers and TbCo layer increases as n is increased. The rough surface provides more obstacles and pinning sites that hinder the motion of the domain walls at interface between the (SiN x /Co) n layers and TbCo layer. Therefore, the H c⊥ values are profoundly influenced by the interface roughness.