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.
Giant interface magnetostriction and temperature dependence in NiFe films encapsulated with Ta and Al/sub 2/O/sub 3/ layers
The interface magnetostriction (MS), /spl lambda//sub i/ of NiFe films (thicknesses:50 to 500 /spl Aring/) encapsulated with Ta and Al/sub 2/O/sub 3/ layers was studied in as-deposited and thermally annealed states. The MS of NiFe films encapsulated with only Ta (or Al/sub 2/O/sub 3/) layers increase (or decrease) rapidly with decreasing NiFe thickness, due to giant positive (or negative) /spl lambda//sub i/. The magnitudes of both positive and negative /spl lambda//sub i/ increase noticeably with processing at elevated temperatures. In structures containing Ta/NiFe and NiFe/Al/sub 2/O/sub 3/ interfaces, the total interfacial MS contribution is greatly reduced due to the opposite signs of /spl lambda//sub i/ at NiFe interfaces, leading to negligible thickness dependence of the effective MS in as-deposited and annealed states. The strong interfacial MS induced anisotropy affects markedly the uniaxial anisotropy of NiFe films for thicknesses below 100 /spl Aring/.
Improvement of RHIC warm beam vacuum for high intensity operation
With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at a few warm vacuum sections. Improvement of the warm sections has been carried out in last year's shutdown. Extensive in-situ bakes, additional UHV pumping, electron detectors and beam tube solenoids have been implemented. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. The effectiveness of these measures in reducing the beam induced pressure bumps and in increasing the vacuum system reliability are discussed and summarized.