Effect of Heat Treatment on Magnetic and Electrical Properties of AlN Films with Co Particles

AlN thin films containing various amounts of Co, AlN-Co, and Al-Co alloy particles were prepared using a two-facing-target type dc reactive sputtering (TFTS) system. The as-deposited films exhibited the variable nature expected from an AlN-rich phase, and an amorphous-like phase, depending on the Co content in the films. Specific favorable microstructures were prepared by optimizing annealing conditions. Those microstructures and their magnetic properties and resistivity were investigated. As-deposited films showed very small saturation magnetization and an amorphous-like structure. However, when annealed, the as-deposited amorphous-like phase decomposes into phases of AlN, Co and Al-Co. These annealing induced changes in the microstructure improve the magnetization and resistivity of the films. Further improvement of soft magnetic properties could lead to the material being used for high density magnetic recording head material.