Fabrication of TbFeCo alloy films with tunable perpendicular coercivity evaluated by extraordinary Hall effect measurements

Rare-earth transition metal (RE-TM) TbFeCo alloy films with adjustable perpendicular switching field and anisotropy are desirable for the applications in high-density spintronic devices. A series of TbFeCo alloy films are fabricated by sputtering a composite target method. The perpendicular magnetic properties of the ferrimagnetic TbFeCo films are investigated by Extraordinary Hall effect (EHE) measurements. With increasing either sputtering power or gas flow rate film composition shifting from FeCo-rich to Tb-rich side is observed and the orientation of magnetic easy axis changing from in-plane, tilted to out-of-plane direction is witnessed. Pronounced change in magnetic properties particularly the coercivity of TbFeCo films is demonstrated, in line with the increased Tb-to-FeCo ratio of the alloy films. It shows TbFeCo films with desirable coercivity can be achieved by proper combination of sputtering power and flow rate. Our work provides an efficient way in tuning the PMA of the sputtered TbFeCo films during the growth and may be used as guidance for designing TbFeCo-based spintronic devices.