CoFeB is a bioinert soft magnetostrictive material, with a switch-like behaviour, useful as transducers for implanted medical devices and wireless power transmission. CoFeB thin-films were investigated in order to determine the influence of three key parameters: film thickness, the application of a magnetic field during deposition, and substrate roughness. CoFeB layers were deposited with different thicknesses and characterised by COMSOL modelling, vibrating sample magnetometry (VSM) and magnetic force microscopy (MFM). A general improvement in magnetic properties was observed by increasing the film thickness, concurrently to a decrease of the boron content, which increased the uniaxial magnetic anisotropy. An enhancement was observed too by the application of a magnetic field for the sputtering of films of 226nm. Notably, 100nm films deposition on rough PET substrates was found to be the most impactful factor in altering the material's ferromagnetism.
Mazón‐Maldonado et al. (2026) studied this question.