Optimal Side Shield Write Head Design for Ultra-High Recording Density

Abstract

In magnetic writing heads, one of the most important factors for ultra-high recording density is the skirt width of write field along cross track direction without degradation of head field and field gradient. The side shield design is known to be the most powerful design for reducing the skirt width. However, the side shields reduce write field and field gradient weak. By finite-element method simulation, we propose the floating (separated) side shield to reduce skirt width without field degradation of write head. As a result, we were able to reduce skirt width from 350 to 250 nm with almost no head field degradation. In addition to increasing the recording density, the separated side shield design provides other benefits to head fabrication by reducing the topography of wafer process. We used design of experiment (DOE) tools, especially response surface method (RSM), to optimize the design. In the simulation, we took into account all soft magnetic materials (write head and soft magnetic underlayer). To verify the results, we checked the correlation between the head field of each shape and adjacent track encroachment (ATE).