The effects of substrate temperature and oxygen pressure on pulsed laser deposited Bi-substituted Dy iron garnet films

Abstract

Polycrystalline thin films of highly Bi substituted Dy iron garnets, [(BixDy3−x(Fe, Ga)5O12], with [111] crystalline orientation perpendicular to the film plane were grown on (111) Gd3Ga5O12, single crystal substrates using pulsed laser deposition technique. In the deposited films, Bi stoichiometry was found to be very sensitive to both substrate temperature and oxygen pressure. The Bi volatilisation problem was relieved by depositing in a high background pressure of oxygen. The results demonstrated that high quality garnet films with large magneto-optical (MO) effects and square hysteresis loops could be obtained when the substrate temperature did not exceed 590°C and the oxygen pressure was kept in the neighbourhood of 0.2 mbar. The MO behaviour of these films compared well with predictions based on the fundamental constants of Bi substituted Yttrium Iron Garnet thick films, grown by liquid phase epitaxy. The coercivity could be varied from a few hundred Oe to several kOe by controlling the oxygen pressure and film thickness.