On the origin of the uniaxial anisotropy in nanocrystalline soft-magnetic materials

Annealing induced uniaxial anisotropy in soft-magnetic nanocrystalline thin films of FeTaN and FeNbSiN has been investigated. It was found that there are several contributions to the uniaxial anisotropy. The direction and the size of some of these can be changed reversibly at temperatures lower than 200 °C, whereas much higher temperatures are needed for others. The nitrogen atoms in these alloys play an important role in the uniaxial anisotropy. The cooling down period is extremely important for the induction of the uniaxial anisotropy. Control of uniaxial anisotropy through appropriate annealing is critical to the application of these materials in magnetic recording devices. Knowledge of the induction, manipulability, and of the thermal stability is essential for finding the optimum annealing procedure and for the application of the material in a magnetic device,