Perpendicular Magnetic Head Pole Layer Tapered Geometry
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in forming a pole layer with a desired shape and achieving accurate track width control, leading to issues like adjacent track erasing and degraded overwrite properties due to differences between physical and effective track widths.
Innovation Solution
A magnetic head design featuring a pole layer with a first portion and a second portion on the medium facing surface, where the second portion has a uniform width defining the track width, and a metal layer with a penetrating opening orthogonal to the substrate, allowing precise control of the track width and reducing the difference between physical and effective track widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the track width is reduced to achieve higher recording density, then the recording density is improved, but the writing characteristics such as overwrite property are degraded
Solution Approach 1:
The pole layer is designed with different width characteristics at different positions: the end portion has a smaller width than the other end, creating a tapered structure. This local variation in geometry allows the track width to be reduced for higher recording density while the tapered shape helps control magnetic field distribution to maintain acceptable overwrite properties.
2Object-affected harmful factors
If the end face of the track width defining portion is made asymmetric to prevent adjacent track erasing, then adjacent track erasing is suppressed, but the manufacturing precision of the pole layer shape becomes more difficult
Solution Approach 1:
The pole layer is divided into multiple portions along the track width direction: a first portion with a first width and a second portion with a second width, where the first width is smaller than the second width. This segmentation allows the asymmetric geometry needed to prevent adjacent track erasing to be implemented while maintaining manufacturability through defined geometric sections.
3Reliability
If the neck height is reduced to improve overwrite property, then the overwrite property is improved, but the writing characteristics are affected
Solution Approach 1:
The invention changes the geometric parameters of the pole layer by creating a tapered end portion with a smaller width than the other end. This parameter variation allows optimization of the neck height and overall geometry to improve overwrite property while maintaining acceptable writing characteristics through the controlled geometric progression.
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 solution enables accurate formation of the pole layer with a desired shape and precise control of track width, improving writing characteristics and reducing adjacent track erasing, thereby enhancing recording density and overwrite properties.
Implementation Method 1
a coil for generating a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
a pole layer made of a magnetic metal material, having an end face located in the medium facing surface, allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough, and generating a write magnetic field for writing the data on the recording medium
Data Source
AI summary
A magnetic head includes an encasing layer made of a nonmagnetic material and having a groove that opens in the top surface; a nonmagnetic metal layer made of a nonmagnetic metal material, disposed on the top surface of the encasing layer, and having a penetrating opening that is contiguous to the groove; and a pole layer made of a magnetic metal material and encased in the groove of the encasing layer and in the opening of the nonmagnetic metal layer. The pole layer has an end face located in a medium facing surface, the end face having a first portion and a second portion that is located farther from a substrate than the first portion and connected to the first portion. The first portion has a width that decreases as the distance from the substrate decreases. The second portion has a uniform width that defines the track width. In the medium facing surface, the nonmagnetic metal layer exists on both sides of the second portion, the sides being opposed to each other in the direction of track width.