The electrical, magnetic and magnetotransport properties of Li–Ni co-doped ZnO thin films were investigated in the electron-dominated, hole-dominated and insulating regimes. In a narrow window of oxygen growth pressure, 10−3–10−2mbar, the films exhibited p-type conductivity with a maximum hole concentration of about 8.2 x 1017/cm3. A magnetoresistance exhibited by the films was attributed to scattering of charge carriers due to localized magnetic moments. Insulating films showed superparamagnetic behavior, whereas both n-type and p-type films exhibited room-temperature ferromagnetism. The findings suggested that oxygen vacancies and Ni ions in cation site were jointly responsible for ferromagnetism that was not dependent on the carrier type.

Oxygen Vacancy Controlled Tunable Magnetic and Electrical Transport Properties of (Li, Ni)-Codoped ZnO Thin Films. E.S.Kumar, S.Venkatesh, M.S.Ramachandra Rao: Applied Physics Letters, 2010, 96[23], 232504