Room temperature ferromagnetism and ferroelectricity behavior of (Cu, Li) co-doped ZnO films deposited by reactive magnetron sputtering

Single-phase Zn0.95−xCuxLi0.05O thin films have been prepared on Pt (1 1 1)/Ti/SiO2 substrates by reactive magnetron sputtering method. The XRD, XPS and absorption measurements confirmed the polycrystalline nature of the films and the substitution of Zn2+ by Cu2+ ions. The sputtered Zn0.90Cu0.05Li0.05O film shows multiferroic properties exhibiting a saturated ferroelectric loop with a remanent polarization of 6 μC/cm2 and a saturated loop with a saturation magnetization of 0.43 μB/Cu at room temperature. The origins of the ferromagnetism and ferroelectricity in these films are discussed.