Sputtering fabrication of GdFeCo alloy films with perpendicular magnetic anisotropy

A series of rare-earth transition metal GdFeCo alloy films are fabricated by sputtering a composite target. The magnetic properties of the GdFeCo films are found to be strongly dependent to sputtering parameters. Typical perpendicular anisotropy of 10(5) erg/cm(3) order in magnitude is demonstrated in the films sputtered at low pressures or using high powers. Proper choosing gas pressure and sputtering power is shown to be critical in achieving perpendicularly magnetized GdFeCo films. A shift of magnetic configuration from FeCo-rich to Gd-rich side is observed in the film with increasing the sputtering power or flow rate. This accompanies pronounced change in magnetic properties of GdFeCo films, in line with increasing Gd-to-FeCo ratio in the films. Our results show sputtering power and flow rate can be used in tuning GdFeCo films with desirable perpendicular magnetic properties.