Post-Annealing Treatments and Interface Effects on Anomalous Magnetic Characteristics of HfOx Film

Interface microstructures and anomalous magnetic characteristics of HfOx film annealed under different conditions have been investigated using X-ray diffraction, X-ray photoelectron spectroscope, high-resolution transmission electron microscopy and superconducting quantum interference device. It is demonstrated that HfOx samples have monoclinic crystal structure and an interface layer of Hf-silicate mixed with Hf-silicide. Remarkable ferromagnetic signals and obvious magnetic anisotropy are observed, and they are greatly affected by the post-annealing temperature and ambient. It is believed that oxygen vacancies and interface defects are responsible for the anomalous magnetic characteristics of HfOx films.