Study on ferromagnetic properties in FeCo-based amorphous thin films with different thickness

Both static and dynamic magnetic properties of amorphous ferromagnetic thin-films were investigated to reveal the effect of thickness-dependent anisotropy and domain wall structure. Amorphous Fe66Co17B16Si1 and Fe39Co39Nb6Cu1B5 alloy thin-films with different thicknesses are deposited on Si for comparison. The increase of thickness results in an indiscipline change of both ferromagnetic resonance and in-plane uniaxial anisotropy at a critical value of 80 nm. The phenomenon is ascribed to the evolution of magnetic domain wall from Néel type to Bloch type as a result of the competition between in-plane and out-of-plane anisotropy. OOMMF is used to simulate the magnetic reversal process, so that the domain wall change is proved.