Role of Cr3+ on Perpenedicular Magnetic Anisotropy in CoCr Ferrite Thin Films for Magneto-Optic Memory

The contribution of Cr³⁺ substitution to perpendicular magnetic anisotropy in CoCr ferrite film fabricated by varying the Cr³⁺ substitution amount was studied. As the Cr³⁺ content increased in the CoCrxFe2-xO4 (x = 0.5, 0.75, 1, 1.25) films, saturation magnetic field decreased and the squareness ratio increased, showing the increase of perpendicular magnetic anisotropy. Films with x greater than 1 had magnetic easy axis perpendicular to the film plane. This result is related to the fact that as Cr³⁺ substitution amount increased, saturation magnetization decreased from 240 emu/cm³ (x = 0.5) to 24 emu/cm³ (x = 1.25).