Ferromagnetic and optical properties of partially Cu-doped ZnO films

Wurtzite structure ZnO films (3×3 mm2) with a partial-area Cu doping were successfully prepared using a micro-area Ar+-ion beam (~380 μm in diameter) and a simultaneous Cu supply at room temperature. A Cu2O phase was formed in the ZnO films by Cu doping. The partially Cu-doped ZnO films exhibited room-temperature ferromagnetism (RTFM) with a saturation magnetization of 1.6×10-5emu and a coercive field of 40 Oe. Since Zn, Cu, and their compounds are not ferromagnetic, the observed RTFM is attributed to the intrinsic property of Cu-doped ZnO films. As confirmed by the low temperature photoluminescence (PL) spectra, no serious optical damage was recognized in the region without Ar+-ion irradiation. Thus, it was believed that the micro-area Ar+-ion irradiation with a simultaneous Cu supply was promising to integrate the magnetic and optical properties of ZnO-based materials.