Control of Magnetic Anisotropy by Lattice Distortion in Cobalt Ferrite Thin Film

We have investigated the properties of cobalt ferrite (CFO)(001) epitaxial thin films grown by RF magnetron sputtering method on various buffer layers to induce large perpendicular magnetic anisotropy (PMA) through the magneto-elastic effect. Among five different compounds examined as the buffer layers, we found that only CFO thin films grown on (Mg, Sn)
₃
O
₄
buffer layers showed a strong PMA, and the value of the saturation magnetization was 460 emu/cm
³
, which is larger than the 425 emu/cm
³
for bulk CFO. Torque measurements revealed the PMA energy K
_u
= 24.6 Merg/cm
³
at room temperature, which is extraordinarily large for a ferromagnetic oxide.