Effect of stress induced anisotropy on SAL-biased MR head performance
The effect of magnetostriction (MS) on the device characteristics of soft-adjacent-layer (SAL) biased magnetoresistive (MR) head was investigated. As MS changes from -7/spl times/10/sup -7/ to 1.77/spl times/10/sup -6/, the magnetic track width increases from 1.26 to 1.83 /spl mu/m. Asymmetry of bias point, output sensitivity, and output amplitude are also affected by the stress induced anisotropy. The variation of magnetostriction (/spl Delta//spl lambda/=2/spl times/10/sup -6/) induces the change in bias field by 60 Oe associated with the estimated stress of +800 MPa on the MR stripe.
Effect of magnetostriction on bias fields in self‐biased MR heads
The effect of magnetostriction on the bias conditions in self‐biased magnetoresistive (MR) heads is reported. In self‐biased MR heads where the bias field is derived from the sense current, the optimum bias point is where the head delivers the maximum output per unit input current. The optimum point depends on the element and head geometry, demagnetizing effects, and the permeability of the MR film. During head construction and operation the MR film is subjected to various sources of stress which can directly affect the permeability of the film and thus the position of this optimum bias point. Many self‐biased MR heads were fabricated using MR elements made from thin (<1000 A) oriented NiFe films with the magnetostriction coefficient close to but varied around zero. The results show quite a marked effect and a correlation between as‐deposited measurements and completed device performance. When the magnetostriction is negative the bias current has to be driven to higher values to achieve the defined optimu...
The influence of substrate edge stress on magnetoresistive head anisotropy
It is found that the film anisotropy H/sub k/, in an unshielded magnetoresistive (UMR) sensor is changed after the establishment of a tape-bearing surface. It is demonstrated experimentally and by a theoretical 2-D stress/micromagnetic treatment of the UMR head configuration that the undesirable change in H/sub k/ is caused by the interaction of an anisotropic stress localized in the vicinity of the lapped tape-bearing surface with the UMR element, which inevitably possesses nonzero magnetostriction. The theory predicts that the change in H/sub k/ can be minimized by minimizing the thickness of the SiO/sub 2/ layers used above and beneath the UMR element. by this means and by minimization of MR element magnetostriction, the intrinsic high sensitivity of the UMR sensor can be preserved in a lapped head. >