Structural and magnetic characterization of ZnCo ₂ O ₄ thin film prepared by pulsed laser deposition

We report the structural and magnetic characterization of ZnCo ₂ O ₄ (ZCO) thin films fabricated by pulsed laser deposition on sapphire substrates. Structural analysis measured by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and atomic force microscope (AFM) shows that the ZCO thin film grew in a layer-by-layer mode, and forms a cubic spinel structure with Fd-3m space group. Electronic states detected by X-ray photoelectron spectroscopy (XPS) prove that Co ²⁺ ions occupied on the Zn sites in the ZCO film and oxygen vacancies exist. Magnetic measurements show a strong ferromagnetic behavior. The possible mechanisms for the ferromagnetic property are extensively discussed. Our work is believed to contribute a good understanding of the microscopic ferromagnetism origin of the high-T _c ZCO film, which is significant for expanding their applications into high-effective spin-electronic devices.