Perpendicular Magnetic Write Head with Tapered Pole and Nonmagnetic Bump
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Solution Overview
Problem
Perpendicular magnetic recording systems face challenges in maximizing write field strength and field gradient while preventing magnetic saturation and adjacent track erasure in magnetic disk drives.
Innovation Solution
A magnetic write head design featuring a magnetic write pole with a non-magnetic step layer, tapered trailing edge, non-magnetic bump, and magnetic trailing shield, which focuses magnetic flux and prevents saturation, thereby enhancing write field strength and field gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a perpendicular magnetic write head is used to maximize write field strength, then data recording density is improved, but magnetic saturation occurs in the write pole
Solution Approach 1:
The write pole structure is modified with different geometric characteristics at different locations: the pole tip maintains a narrow width for field concentration, while the pole body incorporates a tapered trailing edge and nonmagnetic bump to control flux distribution. This local differentiation allows the pole to achieve high write field strength at the tip without saturating the entire pole structure.
Solution Approach 2:
A nonmagnetic bump is introduced as an intermediary element between the write pole and the trailing shield. This nonmagnetic material acts as a flux barrier that prevents magnetic flux from short-circuiting through the shield, thereby maintaining high write field strength while preventing saturation in the write pole and adjacent track erasure.
2Productivity
If write field strength is increased to improve recording speed, then data recording speed is improved, but adjacent track erasure occurs
Solution Approach 1:
The trailing shield is designed with a tapered trailing edge that creates a localized magnetic field gradient. This geometric modification concentrates the write field at the intended track location while rapidly reducing field strength in adjacent regions, thereby preventing adjacent track erasure even at high recording speeds.
Solution Approach 2:
The nonmagnetic bump serves as a flux barrier that confines magnetic flux to the desired track area. By blocking flux leakage into adjacent tracks, the nonmagnetic bump enables higher write field strengths to be used without causing adjacent track erasure, thus improving recording speed.
3Quantity of substance
If field gradient is maximized to enhance recording density, then data recording density is improved, but magnetic saturation occurs in the write pole
Solution Approach 1:
The write pole incorporates a tapered trailing edge that creates a localized region of high field gradient at the pole tip while the rest of the pole structure maintains geometry that prevents flux concentration. This allows high field gradient for dense recording without saturating the entire write pole.
Solution Approach 2:
The nonmagnetic bump acts as a flux barrier that enhances field gradient by preventing flux leakage paths. This intermediary structure allows the magnetic circuit to achieve higher field gradients for improved recording density while the bump itself prevents saturation by blocking excessive flux concentration in the write pole.
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 effectively maximizes write field strength and field gradient, preventing magnetic saturation and adjacent track erasure, leading to improved data recording speed and density.
Implementation Method 1
the nonmagnetic bump and tapered trailing edge focus magnetic flux to the write pole tip
Implementation Method 2
Current conducted to the coil layer induces a magnetic flux in the pole pieces which causes a magnetic field to fringe out at a write gap
Implementation Method 3
a magnetic trailing shield formed over at least a portion of the nonmagnetic trailing gap layer
Data Source
AI summary
A magnetic write head having a write pole with a tapered trailing edge. The write head has a non-magnetic step layer and a non-magnetic bump formed on the front edge of the magnetic step layer. A non-magnetic trailing gap layer is formed over the tapered trailing edge of the write pole and over the non-magnetic bump and over the non-magnetic step layer. A magnetic trailing shield is formed over at least a portion of the non-magnetic gap layer.