Controllable rotation of magnetic anisotropy in FeCoB films by sputtering pressure

FeCoB films with gradient B doping were deposited by a composition gradient sputtering method under different sputtering pressure. Good soft magnetic performances with magnetic anisotropy field of 142 Oe and ferromagnetic resonance frequency of 4.82 GHz were obtained at zero bias field. It is interesting to note that the magnetic anisotropy of the films rotates by 90° by changing the sputtering pressure from 0.2 to 0.5 Pa, which can be attributed to the stress transition from compressive to tensile. This provides a possible method to in-situ construct complex magnetic anisotropy by controlling the sputtering pressure.