Enhanced grain growth of magnetic granules in Co/oxide granular films

We have investigated phase separation and grain growth of Co in Co-(Si, Sm, In, Si-In)-O granular films and found significant grain growth in Co-In-O at low annealing temperature. Using this non-magnetic matrix, the annealing temperature necessary for optimal granular structures can be reduced significantly compared with conventional Co-Si-O and Co-Sm-O granular systems. A newly proposed phase separation model based on the bonding energy of constituent elements qualitatively explains all the experimental results