The effect of oxygen vacancies on ferromagnetism in Zn1-xMnxO thin films grown by radio frequency sputtering was investigated. The grown films at different oxygen pressures were characterized by X-ray diffraction, Hall effect, photoluminescence and vibrating sample magnetometry. The observed ferromagnetism/diamagnetism by the vibrating sample magnetometry measurement due to the variation of oxygen vacancies was confirmed by X-ray diffraction, photoluminescence and Hall results. The vacancy-mediated ferromagnetism was explained by the formation of magnetic polarons.

Vacancy-Mediated Room-Temperature Ferromagnetism in Zn1-xMnxO Thin Films. Gopalakrishnan, N., Balakrishnan, L., Srimathy, B., Kumar, M.S., Balasubramanian, T.: Physica Status Solidi A, 2010, 207[9], 2180–4