Magnetic properties and microstructures of single-layered Fe100 − xPtx films deposited onto heated substrates

The single-layered Fe100 − xPtx films of 30 nm thick with Pt contents (x) of 35–57 at.% are deposited on heated Si (100) substrate at a temperature (Ts) of 620 °C by magnetron co-sputtering. When the Pt content in the Fe–Pt alloy film is 35 at.%, the value of in-plane coercivity (Hc//) is close to perpendicular coercivity (Hc⊥) and both values are about 800 kA/m. The FePt films exhibit perpendicular magnetic anisotropy when the Pt content increases to the values of between 45 and 51 at.%. The perpendicular coercivity, saturation magnetization (Ms) and perpendicular squareness (S⊥) for Fe54Pt46 film are as high as 1113 kA/m, 0.594 Wb/m2 and 0.96, respectively. These magnetic properties reveal its significant potential as perpendicular magnetic recording media. Upon further increasing the Pt content to 57 at.%, the coercivity of the Fe–Pt film decreases drastically to below 230 kA/m and tends to be closer to in-plane magnetic anisotropy.