Structural and magnetic properties of ZnFe₂O₄ films deposited by low sputtering power

To validate the correctness of the Hartman-Perdok Theory (HPT), which indicates that the {111} planes have the lowest surface energy in spinel ferrites, the {111} plane orientated ZnFe₂O₄ thin films on Si(100), Si(111), and SiO₂(500 nm)/Si(111) substrates were obtained through a radio frequency (RF) magnetron sputtering method with a low sputtering power of 80 W. All of the experiments prove that the atom energy determined by sputtering power plays an important role in the orientated growth of the ZnFe₂O₄ thin films, and it matches well with HPT. The ZnFe₂O₄ thin films exhibit ferromagnetism with a magnetization of 84.25 kJ/mol at room temperature, which is different from the bulk counterpart (antiferromagnetic as usual). The ZnFe₂O₄ thin films can be used as high-quality oriented inducing buffer layers for other spinel (Ni, Mn)Zn ferrite thin films and may have high potential in magnetic thin films-based devices.