Effects of post-annealing on the magnetic properties of FeCoBN thin film

Below a critical thickness (∼100 nm), FeCoBN thin films showed excellent soft magnetic properties and high-frequency characteristics. However, it was found that the residual stress sharply degraded their properties over the critical thickness. In order to overcome this limit, magnetic post-annealing process has been carried out in this experiment. The microstructural analysis showed that the annealing effectively removed the residual stress of FeCoBN films without any microstructural changes. This removal improved the soft magnetic properties and high-frequency characteristics of the films of which the thickness was over the critical thickness.