Raman spectra and room-temperature ferromagnetism of hydrogenated Zn0.95Mn0.05O nanopowders

Two additional vibration modes at 250 and 529 cm(-1) were observed in hydrogenated Zn0.98Mn0.05O nanopowders. The number of oxygen vacancies was increased by hydrogenation, which induced the mode at 250 cm(-1). The additional vibration mode at 529 cm(-1) was due to the increase of the number of subsititutional Mn atoms occupying Zn sites, which resulted that some new lattice defects were introduced or intrinsic host-lattice defects became activated/intensified. The room-temperature ferromagnetism was observed in the hydrogenated Zn0.98Mn0.05O nanopowders prepared at high temperature (T=700 degrees C), which originated from the lattice defects such as oxygen vacancies and Zn interstitials. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3147867]