Thin-Film Magnetic Head Shield Layer Segmentation for Narrow Free Layer
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Solution Overview
Problem
Conventional thin-film magnetic heads with a CPP structure face challenges in narrowing the read gap to achieve higher resolution due to over-etching of the lower magnetic shield layer, which reduces the shield effect and deteriorates bit resolution.
Innovation Solution
A thin-film magnetic head design where a second soft magnetic layer is formed outside the side ends of the MR multi-layered structure by over-etching the lower magnetic shield layer, preventing the lowering of the shield effect and allowing for narrower free layer widths, with the second soft magnetic layer being laminated to maintain or enhance the shield effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If excess milling is performed to narrow the width of the free layer, then the width of the free layer is narrowed, but the lower magnetic shield layer is over-etched causing reduction in shield effect and deterioration of bit resolution
Solution Approach 1:
The lower magnetic shield layer is divided into two separate layers: a first soft magnetic layer and a second soft magnetic layer. The first layer is over-etched to narrow the free layer width, while the second layer is deposited afterward to restore the shield effect at the end surfaces, thus resolving the contradiction between narrowing the free layer and maintaining the shield effect
Solution Approach 2:
The first soft magnetic layer is prepared in advance and intentionally over-etched to achieve the desired narrow free layer width. Then the second soft magnetic layer is deposited as a subsequent action to compensate for the shield effect loss, ensuring both goals are achieved in sequence
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables the narrowing of the free layer width without compromising the shield effect, thereby improving the resolution of the thin-film magnetic head in the track-width direction.
Implementation Method 1
thin-film magnetic head with a magnetoresistive effect (MR) element for detecting magnetic intensity in a magnetic recording medium and for outputting a read signal
Implementation Method 2
a first soft magnetic layer and a second soft magnetic layer laminated on and magnetically connected with the first soft magnetic layer
Data Source
AI summary
A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, and an upper magnetic shield layer formed on the MR multi-layered structure. The lower magnetic shield layer consists of a first soft magnetic layer and a second soft magnetic layer laminated on and magnetically connected with the first soft magnetic layer. A part of an upper surface of the first soft magnetic layer outside both side ends in a track-width direction of the MR multi-layered structure is located lower in height than an upper surface within a region where the MR multi-layered structure is formed, of the lower magnetic shield layer. The second soft magnetic layer is formed outside both side ends in a track-width direction of the MR multi-layered structure.