Perpendicular Magnetic Head Pole Interval Design
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Solution Overview
Problem
Conventional perpendicular magnetic recording heads face challenges in maintaining recording performance when reducing the thickness of the main pole to achieve narrower recording track widths, leading to decreased magnetic field strength and gradient, which affects storage density and data integrity.
Innovation Solution
A perpendicular recording magnetic head design featuring a main pole with a flare portion, a magnetic-field auxiliary pole, and a nonmagnetic layer, along with a shield on the trailing side, where the nonmagnetic layer is positioned to maintain magnetic field strength and gradient, and the shield's interval is adjusted to prevent magnetic field loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the thickness of the main pole is reduced to achieve narrower recording track widths, then recording track width is reduced and surface recording density is improved, but magnetic field strength and magnetic field gradient decrease, leading to degraded recording performance
Solution Approach 1:
The magnetic head is divided into multiple functional components: main pole, auxiliary pole, and shield, each with specific intervals and configurations. The auxiliary pole is positioned at a predetermined interval from the main pole, and the shield is positioned at a different interval, creating segmented magnetic field zones that collectively enhance magnetic field strength while maintaining narrow track width
Solution Approach 2:
A nonmagnetic layer is introduced as an intermediary between the auxiliary pole and the shield. This nonmagnetic layer prevents unwanted magnetic interaction between these components while allowing the auxiliary pole to effectively enhance the magnetic field from the main pole, thereby maintaining strong magnetic field strength with reduced main pole thickness
2Manufacturing precision
If the thickness of the main pole is reduced to achieve narrower recording track widths, then surface recording density is improved, but magnetic field gradient decreases, affecting data integrity
Solution Approach 1:
The magnetic head structure is segmented into main pole, auxiliary pole, and shield with specific spatial relationships. The auxiliary pole is positioned to enhance magnetic field gradient in the recording region, while the shield is positioned to contain the magnetic field, collectively maintaining data integrity even with reduced main pole thickness
Solution Approach 2:
Different regions of the magnetic head are given different properties: the auxiliary pole region is designed to enhance magnetic field gradient locally, the nonmagnetic layer region prevents magnetic flux leakage, and the shield region contains the magnetic field. This local optimization maintains overall system reliability while enabling higher recording density
3Ease of manufacture
If a rectangular main pole flying surface is used, then manufacturing is simplified, but adjacent track erasure occurs, leading to data loss
Solution Approach 1:
The main pole flying surface is designed with asymmetric dimensions: the width in the track width direction is different from the width in the track length direction. Specifically, the width in the track length direction is made larger to prevent adjacent track erasure, while the width in the track width direction is controlled to maintain narrow track width. This asymmetric design simultaneously achieves manufacturing feasibility and data integrity
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 enhances magnetic field strength and gradient, allowing for increased recording density without degrading performance, enabling higher surface recording densities while maintaining data integrity across the magnetic disk.
Implementation Method 1
a perpendicular recording magnetic head includes a main pole, comprising a track portion that defines a recording track width and a flare portion that is formed integrally with the track portion and gradually increases in width in an element height direction. A magnetic-field auxiliary pole and a nonmagnetic layer are stacked on the flare portion
Implementation Method 2
an auxiliary pole and a shield provided on a trailing side and each cross track side of the main pole. In addition, an interval between the main pole and the shield provided on the trailing side is larger at a position from which the nonmagnetic layer is provided than at a position of a flying surface
Data Source
AI summary
A perpendicular recording magnetic head is provided, according to one embodiment, in which even if a thickness of a main pole is reduced corresponding to a reduction in a recording track width, recording performance is not degraded. A magnetic-field auxiliary pole and a nonmagnetic layer are stacked on a main pole, and a nonmagnetic portion is provided on each side face on a flying surface side of the magnetic-field auxiliary pole and the nonmagnetic layer, in one approach. In all regions except for a region near a flying surface, an interval between the main pole and a shield is increased by the nonmagnetic portion and the nonmagnetic layer, so that magnetic field loss is prevented, and consequently magnetic field strength and a magnetic field gradient are increased. Other systems and methods are also disclosed for retaining magnetic recording performance while reducing a thickness of a main pole.