Magnetic Properties of Ultrathin $\gamma \hbox{-}\hbox{Fe}_{2}\hbox{O}_{3}$ Films Grown on Silicon Substrate

The effect of thickness and annealing temperature on the room-temperature magnetic properties of ultrathin γ-Fe
₂
O
₃
films grown on silicon substrate were investigated. Ultrathin γ-Fe
₂
O
₃
films were grown on silicon substrates by ion beam sputtering. The saturation magnetization and coercive force of samples at room temperature increase with increasing of annealing temperature and decrease at annealing temperatures above 600
^°
C. The saturation magnetization of samples at room temperature decreases with increasing of γ-Fe
₂
O
₃
thickness. The γ-Fe
₂
O
₃
samples about 3 ~ 6 nm thick annealed at 600
^°
C show saturation magnetization of about 360 ~ 410 emu/cm
³
, which is close to the bulk value of about 390 emu/cm
³
within the error range.