High-frequency ferromagnetic properties and magnetic domain structures of FeNdBO thin films.

FeNdBO films were deposited by DC magnetron sputtering. The high-frequency ferromagnetic properties of the films were dramatically enhanced by annealing at 350 degrees C for 1 hour. In comparison with the as-deposited film, the resonance frequency increased from 1.32 to over 3 GHz, while relative permeability still maintained at a high value of 100. Magnetic force microscope (MFM) revealed strip domains in the FeNdBO films. The domain width of approximately 100 nm for the annealed film was smaller than that for the as-deposited film, implying the enhancement of anisotropy field due to annealing. Promising high-frequency ferromagnetic properties of FeNdBO films can be attributed to the high values of Ms (15.7 kG), Hk (over 1000 Oe), and p (more than 10 Omegam).