Hydrogenation-induced room-temperature ferromagnetism in Co-doped ZnO nanocrystals

The room-temperature ferromagnetism properties of Co-doped ZnO nanocrystals are reported in this paper. Zn1-xCoxO (0.0 < x < 0.06) specimens were synthesized by an aqueous solution method. The specimens were then hydrogenated at 600-800??:C for 1 h. Room-temperature ferromagnetism (RTFM) was observed in the hydrogenated samples, and the hysteresis loops of the hydrogenated Co-doped ZnO samples were measured at 300 K using a vibrating sample magnetometer (VSM). The samples were further measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) with analysis energy dispersive X-ray spectroscopy (EDX). ? 2008 The Japan Society of Applied Physics.EI4 PART 23261-32634