Stress induced anisotropy effect for SAL films in magnetoresistive elements

The stress configuration of SAL (soft adjacent layer)-biased magnetoresistive (MR) elements has been analyzed, in order to study the stress-induced anisotropy effect on the MR transfer characteristics. The stress analysis, on the basis of stress measurement results in the single-layer sheet films that formed the MR elements, shows that anisotropic tensile stress of around 100 to 300 MPa is induced in the element height direction in the SAL film with an open-pattern edge structure. Furthermore, we calculated the MR transfer curves using a micromagnetic model for samples with different saturation magnetostriction constant (λ_s) value for SAL films. Assuming anisotropic tensile stress of 300 MPa in the element height direction throughout the entire track region, a desirable λ_s value for SAL films is in the range from +1×10^-6 to -2×10^-6, because the stress-induced anisotropy in the SAL does not seriously affect the μR transfer curves