Sputtered Mn-Al-Cu films for magnetic recording media

Ferromagnetic τ phase of Mn-Al-Cu films have been prepared by dc magnetron sputtering and their crystallographic characteristics, magnetic properties and recording characteristics have been investigated. In binary Mn-Al films, the stability of τ phase is very poor and saturation magnetization Ms as low as about 120 emu/cc. To improve the stabilty of this phase and increase the Ms, Mn was partially substituted by Cu. Ms increased from 120 to 300 emu/cc with increase in Cu content of up to 23 at%. Coercivity Hc decreased with increase of Cu content in the films. τ and κ phase were synthesized at Cu content below 10 at% and above this content, respectively. MnAlCu thin film sputtered disks have been prepared and their recording characteristics have been investigated. Typical recording density D50of MnAlCu disk was 59 kfrpi.