Field annealing effect on magnetostriction and sensitivity of the ferromagnetic Fe60Co18Ga22/Si(1 0 0) film

Abstract As-deposit (AD) and field-anneal (FA) Fe 60 Co 18 Ga 22 films have been made. We found that after FA treatment, both the macro-stress and saturation magnetostriction in the film increase greatly. Also, after FA treatment, the tetragonal L1 2 phase shows up, and coexists within the original two-phase (A2 + D0 3 ) field. In agreement with the theory, the occurrence of large stress and magnetostriction is related to the magnetic-field-induced flip of the tetragonal axis of the L1 2 phase crystal by FA. As a low-field sensor, FA could enhance the sensitivity of the Fe 60 Co 18 Ga 22 film element up to 18.9 ppm/Oe.