(07C108) Magnetic properties of ultrathin single crystal Fe_3O_4 film on lnAs(100) by ferromagnetic resonance

摘要

The evolution of both in-plane and out-of-plane magnetic anisotropies has been studied on different thicknesses of Fe_3O_4/InAs(100) hybrid spintronic structures by ferromagnetic resonance. The uniaxial magnetic anisotropy with easy axis along InAs [011] direction and hard axis along [0-11] direction and the cubic magnetic anisotropy are determined by fitting the resonance field. The cubic magnetic anisotropy constant K_1 is negative, as that of bulk magnetite, and its absolute value increases rapidly from 0.2 × 10~4 erg/cm~3 to 10.8 × 10~4 erg/cm~3 with increasing thickness of Fe_3O_4 film. When the thickness of Fe_3O_4 film is only several monolayers (t_(Fe) = 6 nm), a bulk-like cubic magneto-crystalline anisotropy is built up. The uniaxial anisotropy constant is much smaller than that in Fe_3O_4/GaAs film with the same thickness of Fe_3O_4 film, as expected from the less lattice mismatch at the interface.