1307.4820 (H. Bieber et al.)

Reduction of conductivity and ferromagnetism induced by Ag doping in
ZnO:Co    [PDF]

H. Bieber, S. Colis, G. Schmerber, V. Pierron-Bohnes, D. W. Boukhvalov, E. Z. Kurmaev, L. D. Finkelstein, P. Bazylewski, A. Moewes, G. S. Chang, A. Dinia

Cobalt and silver co-doping has been undertaken in ZnO thin films grown by pulsed laser deposition in order to investigate the ferromagnetic properties in ZnO-based diluted magnetic materials and to understand the eventual relation between ferromagnetism and charge carriers. Hall transport measurements reveal that Ag doping up to 5% leads to a progressive compensation of the native n-type carriers. The magnetization curves show ferromagnetic contributions for all samples at both 5 K and room temperature, decreasing with increasing the Ag concentration. First principles modeling of the possible configurations of Co-Ag defects suggest the formation of nano-clusters around interstitial Co impurity as the origin of the ferromagnetism. The Ag co-doping results in a decrease of the total spin of these clusters and of the Curie temperature.

View original: http://arxiv.org/abs/1307.4820