Angled Magnetic Pole Layer for Perpendicular Recording
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in achieving high recording density and preventing issues like adjacent track erasing and unwanted writing due to skew, which affect write characteristics and signal quality.
Innovation Solution
A magnetic head design featuring a pole layer with a first portion inclined at 12 to 45 degrees relative to the medium facing surface, a nonmagnetic layer on the second portion, and a shield with a gap layer between the pole layer and the shield, allowing for precise control of magnetic flux and reducing flux leakage, thereby improving write characteristics and preventing skew-related problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the track width is reduced to achieve higher recording density, then recording density is improved, but write characteristics such as overwrite property deteriorate
Solution Approach 1:
The pole layer is designed with non-uniform thickness: a first portion with smaller thickness near the medium facing surface and a second portion with larger thickness farther from the surface. This local variation allows the thinner first portion to define precise track width for high recording density while the thicker second portion provides sufficient magnetic flux for good write characteristics including overwrite property.
2Reliability
If the neck height is reduced to improve overwrite property, then write characteristics are improved, but track width definition precision deteriorates
Solution Approach 1:
The pole layer thickness is locally optimized with a smaller thickness in the first portion at the neck region to improve overwrite property, while maintaining a larger thickness in the second portion to ensure precise track width definition. This local differentiation resolves the contradiction between overwrite capability and track width precision.
3Reliability
If the pole layer thickness is reduced to improve write characteristics, then overwrite property is improved, but magnetic flux introduction capability deteriorates
Solution Approach 1:
The pole layer employs local thickness variation: the first portion has smaller thickness to enhance overwrite property by reducing magnetic flux leakage, while the second portion has larger thickness to maintain strong magnetic flux introduction capability. This spatial differentiation of thickness allows both contradictory requirements to be satisfied simultaneously.
4Reliability
If a shield is added to prevent adjacent track erasing, then track isolation is improved, but device complexity increases
Solution Approach 1:
The shield is positioned asymmetrically relative to the pole layer, with the gap between the shield and pole layer varying in the track width direction. This asymmetric configuration provides effective magnetic flux shielding to prevent adjacent track erasing while minimizing the shield dimensions and overall structural complexity.
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
The design enhances write characteristics by allowing greater magnetic flux to the medium facing surface, reduces flux leakage, and maintains precise track width definition, addressing the issues of adjacent track erasing and signal quality degradation.
Implementation Method 1
a coil for generating a magnetic field corresponding to data to be written on a recording medium; a pole layer allowing a magnetic flux corresponding to the magnetic field generated by the coil to pass therethrough and generating a write magnetic field
Implementation Method 2
a shield made of a magnetic material and having an end face located in the medium facing surface at a position forward of the end face of the pole layer
Data Source
AI summary
A magnetic head includes: a pole layer; a nonmagnetic layer disposed on part of the top surface of the pole layer; a gap layer disposed on the pole layer and the nonmagnetic layer; and a shield disposed on the gap layer. The top surface of the pole layer includes: a first portion having a first edge located in a medium facing surface and a second edge opposite thereto; and a second portion located farther from the medium facing surface than the first portion and connected to the first portion at the second edge. The first portion is inclined with respect to a direction orthogonal to the medium facing surface so that the distance from a substrate increases with increasing distance from the medium facing surface. The nonmagnetic layer has a bottom surface touching the second portion, and this bottom surface has an edge located at the second edge.