CARRIER GENERATION RECOMBINATION IN THE RESISTIVITY DECAY PROCESS OF CA-YIG FILMS/

Ca:YIG has many electrical properties similar to those of magnetic sem iconductors including resistivities as low as a hundred Omega cm and a ctivation energies of 0.2-0.4 eV. In this paper a resistivity decay pr ocess in Ca:YIG when exposed for long periods to moderate electric fie lds is reported. Resistivities are reduced by 10(7) and activation ene rgies by a factor of three are quite stable. A model explains the phen omena in terms of a hole generation/recombination process at repulsive trap sites. Impact ionization dominates the resistivity decay process and the repulsive barrier heights are in the energy range of 0.8-1.2 eV. The structural defect is postulated to be a singly charged oxygen vacancy. (C) 1998 Elsevier Science B.V. All rights reserved.