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.
Anistrophy changes in magnetorestistive heads due to lapping and annealing
The elimination of Barkhausen noise in order to attain stable read performance is of primary interest in magnetoresistive (MR) read heads. One approach to making MR elements stable is to make the effective uniaxial anisotropy field large with respect to the hard axis fields experienced during operation and storage. In addition to providing a stabilizing effect, the anisotropy field determines the sensitivity of the element. A simple measurement of sensitivity at the component level is used to evaluate the effects of lapping and annealing. Analysis of sensitivity data, measured transfer functions, and calculated transfer functions shows that the stress-induced anisotropy can be reduced by magnetic annealing. Recording tests with unshielded, annealed, read-only heads reading a track recorded by a separate head show that the read signal is stable and free of Barkhausen noise for externally applied hard axis fields of up to 100 Oe. However, this stability comes at the cost of lower sensitivity hence lower readback signal level. A balance of stability and output can be achieved by adjusting the magnetocrystalline anisotropy, the magnetostriction, or the thermally induced stress and by the use of annealing after final lapping. >
5.63 and 5.80 MeV levels of Ne20; de-excitation branching
Abstract The ratio Г γ /Г for the 5.63 and 5.80 MeV levels of Ne 20 has been determined to be 0.077 (±0.008) and −4 , respectively, by using the C 12 (C 12 , α)Ne 20 reaction and determining the fraction of the events in which the alpha-particle and the Ne 20 recoil are present in coincidence at the kinematically correct angles. In both cases these results in themselves are shown to imply radiative E1 transition (5.63→1.63 and 5.80→0, respectively) probabilities ⪡5 × 10 −5 Weisskopf units. When taken together with the life-time for the 5.63 MeV level measured by Evans et al . values of Г( E1 ) ≲ 5 × 10 −6 and Г α ≈ 6% of the particle estimate are obtained for this state.