Anomalously large magnetic moment in nanocrystalline Co0.3Zn0.7Fe2O4 thin films

Co0.3Zn0.7Fe2O4 nanocrystalline thin films were deposited by pulsed laser ablation technique on amorphous quartz substrate. These films were as deposited at different substrate temperatures (T-S) varying from room temperature (RT) to 750 degrees C. The RT deposited films were ex situ annealed at annealing temperatures (T-A) ranging from 150 degrees C to 750 degrees C. The magnetic properties of the films were observed to depend on T-A and T-S. A spontaneous magnetization (4 pi M-S) value higher than that of the bulk was observed in the as deposited film at T-S = 750 degrees C. This film also showed a higher Curie temperature than bulk. These results were explained based on the grain growth and cation distribution in thin films.