Magneto-optical studies of Sm(Fe,Ti)₁₂ perpendicular textured sputtered films

Measurements of the polar Kerr rotation and optical coercivity as a function of photon energy have been made on ≊2 μm thick ThMn 12-type crystalline sputtered films of Sm(Fe,Ti)12. The optical coercivity for a Ti containing (222) textured film was 3.10 kOe at a photon energy of 1.25 eV, 2.96 kOe at 1.84 eV, and 2.92 kOe at 2.45 eV. The optical coercivity for a similar composition (002) textured Sm(Fe,Ti) 12 film was relatively constant at 1.24 kOe. These samples were measured in air at 300 K without any protective overcoating. The polar Kerr rotation observed for these crystalline films versus the photon energy paralleled that observed for pure Fe. The magnetometer and optical coercivities for the (222) textured Sm(Fe,Ti)12 films were 1.5 and 2.5 times as large, respectively, as for similar composition (002) textured films. Differences in grain sizes incorporated during the direct synthesis of the films onto heated substrates are needed to account for the large differences observed in the coercivities for the (222) versus (002) textured films.