Rare-earth-mediated magnetism and magneto-optical Kerr effects in nanocrystalline CoFeMn0.9RE0.1O4 thin films

A series of rare-earth (RE)-doped nanocrystalline CoFeMn0.9RE0.1O4 thin films were prepared on monocrystalline silicon substrate by a sol-gel process, and the influences of the various RE3+ ions on the microstructure, magnetism and polar magneto-optical Kerr effects of the as-deposited films were examined. The results revealed that both of the magnetism and Kerr effect of CoFeMn0.9RE0.1O4 films could be mediated by doping with various RE3+ ions. The trend of both MS and HC of CoFeMn0.9RE0.1O4 films is similar to that of Bohr magneton across the series of rare-earth ions. The position of Kerr rotation peaks was red-shifted and their intensities increased, especially when doping with La3+, Tb3+, Y3+ or Yb3+ and so on. The enhanced MOKEs in CoFeMn0.9RE0.1O4 nanocrystalline thin films might promise their applications for magneto-optical recording in the future