XPS characterization of YAlO3:Co single crystals

YAlO3:Co (YAP:Co) single crystals have been obtained by the Czochralski method. The XPS spectra of YAP:Co annealed in reducing atmospheres: H2, vacuum and vacuum plus H2 are presented and discussed. As confirmed by magnetic measurements and the electron spectroscopy XPS the dopant concentration of Co is lower than a nominal one. The annealing processes removed colour centers due to relocation and some reduction of oxygen ions in the structure. The increased unit volume during the long annealing process may be caused by the change in some Co3+ ions into Co2+ ions. This explains the occurrence of the violet colour of the longtime annealed samples. The chemical shift analysis shows more ionic bond of Y–O than Al–O. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)