Spin reorientation in single-crystal CoFe₂O₄ thin films

Reorientation of magnetic anisotropy has been observed in single-crystal CoFe2O4 thin films deposited on (100)MgO substrate by pulsed laser deposition (PLD). The as-grown film exhibits a perpendicular anisotropy whereas after annealing the magnetization easy axis switches to be parallel to the film plane. The origin of such spin reorientation is explained in terms of competition between stress and magnetocrystalline anisotropies. The as-prepared film is under tensile stress, which induces a huge perpendicular uniaxial anisotropy dominating the in-plane magnetocrystalline component. Annealing releases the stress by relaxing the film lattice. Consequently, the perpendicular stress anisotropy is considerably reduced andmagnetocrystalline anisotropy prevails, leading to an in-plane alignment of the easy axis.