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/.
A new high-precision optical technique to measure magnetostriction of a thin magnetic film deposited on a substrate
The drive in data storage technology towards utilizing magnetic films with lower magnetostriction (to reduce the magnetoelastic energy term) and reduced thickness has resulted in the requirement for more sensitive, reliable, and easy-to-use tools to monitor magnetostriction. A measurement tool based on an in-plane rotating and saturating magnetic field and laser-beam-deflection technique, which is able to meet these requirements, is described. The tool developed offers high accuracy, large dynamic range, long-term stability, simple sample insertion, and a fast, easy measurement procedure. With this tool, the measurement of small magnetostriction coefficients of thin soft-magnetic films can become a simple, fast, and reliable procedure, thus helping the development of magnetic thin-film production processes and routine composition control. >