Nonlinear transition shifts in magnetic recording due to interpattern proximity effects

Abstract

A high-precision measurement of the proximity shift on a magnetic transition due to the presence of an old transition in the background is presented. Using peak detection electronics, this interpattern shift was deduced by measuring the distance between a reference and a test transition in a multibit pattern, with and without a background transition in the vicinity of the test transition. The measurement process was carefully designed to achieve high accuracy. The proximity shift of a 3380-type write head on disks with different remenent-thickness product for cases of both easy and hard transition types was measured for both the background and the data transitions. Results showed three distinct transition-shift behaviors depending on the background-to-test intertransition distance: a gradual decay in the far region (≳2 μm), a rapid rise in the intermediate region, and asymptotic saturation at the near region when the two transitions are almost on top of each other. The asymptotic shift magnitude agrees well with independently measured hard-transition shifts, and good agreement with theoretical modeling is obtained for shifts in the far and intermediate regions.