Thickness-Dependent Magnetic Properties of Patterned FeCoBSi Amorphous Thin Films on Silicon Substrate

A FeCoBSi thin film with different thicknesses was deposited on Si (111) substrate by controlling the sputtering time under applied magnetic field and then patterned into strips with fixed width and length by conventional optical lithography. The magnetic properties of the films were investigated. Patterned FeCoBSi strips show an obvious tunable in-plane uniaxial magnetic aniostropy property in contrast with as-deposited FeCoBSi thin films. The values of effective magnetic aniostropy of the patterned films increase as the thickness increase. The tunable in-plane anisotropy field of FeCoBSi strips result in tunable high-frequency soft magnetic properties by altering the thickness of films. The ferromagnetic resonance frequency (f_r)showed a corresponding increment from 2 to 6.9 GHz. It indicated that the patterned FeCoBSi strips have great potential in high-frequency soft magnetic application fields.