Room-temperature Ferromagnetic Zn0.95Co0.05O Diluted Magnetic Semiconducting Thin Films by Pulsed Laser Deposition

ABSTRACTCo-doped ZnO thin films with room-temperature ferromagnetism have been successfully synthesized on (001) Si substrates at 450 °C by pulsed-laser deposition using a Zn0.95Co0.05O ceramic target. Their microstructural properties are carefully studied using atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy. The oxidation state of Co and the ratio of Co/Zn are examined by x-ray photoelectron spectroscopy, and magnetic measurements are performed using SQUID. The results show that a single-phase crystalline Co-doped ZnO film was grown with (002) preferential orientation and some edge dislocations formed during the film growth. The origin of room-temperature ferromagnetism is explored. The presence of nanoclusters of any magnetic phase can be ruled out. The dislocations, coupled with oxygen vacancy, may contribute to the ferromagnetic properties in the much diluted magnetic semiconductor.