MAGNETIC-BEHAVIOR OF NANOCRYSTALLINE COBALT FERRITE FILMS

When prepared with a nanocrystalline structure, cobalt ferrite films o ften exhibit very low magnetization compared with that of the bulk mat erial. We report here on low-temperature magnetization measurements wh ich show that the long-range ferrimagnetic order is broken in the film s and that a glassy behavior results. Even though we cannot ascertain the nature of the magnetic disorder, our data are consistent with the molecular field theory of Ising spin glasses with strong ferromagnetic interactions.