Tapered Magnetic Write Pole with Asymmetric Side Shield Angles
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Solution Overview
Problem
Magnetic write heads face challenges in maintaining strong magnetic write field strength while minimizing adjacent and far track interference, which occurs due to reduced write pole size and magnetic flux leakage to side shields.
Innovation Solution
A magnetic write head with a multi-layer side gap structure featuring a write pole with a first bevel and flare angle, and a side shield with a second bevel and flare angle, where the bevel angle of the write pole is greater than that of the side shield, and the flare angle of the side gap is greater than that of the write pole, forming a non-magnetic gap between the side shield and the write pole to reduce magnetic flux leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the write pole size is reduced to increase data density, then the data storage capacity is improved, but the magnetic write field strength decreases and track interference increases
Solution Approach 1:
The write pole is designed with different geometries at different locations: a tapered shape along the length to concentrate flux at the tip, and a beveled edge at the leading end to control field distribution. This local variation in geometry allows the small write pole to generate sufficient write field strength while limiting lateral field spread that causes interference.
Solution Approach 2:
The invention optimizes specific geometric parameters of the write pole including the taper angle (controlling flux concentration) and bevel angle (controlling field spread). By carefully selecting these parameters, the write pole maintains strong magnetic field at the tip for effective writing while reducing far track interference.
2Strength
If the write pole is tapered to concentrate magnetic flux, then the magnetic write field strength is improved, but magnetic flux leaks to the sides causing adjacent track and far track interference
Solution Approach 1:
The write pole combines a tapered section (for flux concentration) with a beveled leading edge (for field containment). The tapered portion concentrates flux to enhance write field strength, while the beveled edge at the leading end controls the angular distribution of the magnetic field, preventing excessive lateral spread that would cause adjacent and far track interference.
Solution Approach 2:
The write pole has an asymmetric geometry with different angles: the taper angle controls the longitudinal flux concentration while the bevel angle controls the lateral field distribution. This asymmetric design allows independent optimization of write field strength and interference reduction.
3Object-generated harmful factors
If a magnetic shield structure is added to reduce far track interference, then the track interference is reduced, but magnetic flux flows into the side shields causing field saturation and domain wall movement
Solution Approach 1:
Instead of using a magnetic shield that directly contacts the write pole, the invention extracts the shielding function by positioning side shields at a distance from the write pole. The gap between the write pole and side shields prevents direct magnetic flux coupling, avoiding field saturation and domain wall movement in the shields while still providing interference reduction.
Solution Approach 2:
A non-magnetic gap structure serves as an intermediary between the write pole and side shields. This gap prevents direct magnetic flux flow into the shields, eliminating the harmful effects of field saturation and domain wall movement while allowing the shields to function for interference reduction.
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 configuration effectively prevents near and far track interference while maintaining high magnetic write field strength, reducing data loss from adjacent and far track interference.
Implementation Method 1
When current flows through the coil, a resulting magnetic field causes a magnetic flux to flow through the coil, which results in a magnetic write field emitting from the tip of the write pole
Implementation Method 2
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor or a Tunnel Junction Magnetoresistive (TMR) sensor can be employed to read a magnetic signal from the magnetic media. The magnetoresistive sensor has an electrical resistance that changes in response to an external magnetic field
Data Source
AI summary
A magnetic write head for magnetic data recording that has a magnetic write pole and a magnetic side shield structure, wherein the flare angle and bevel angle of the write pole are different from the flare angle and bevel angle of the magnetic side shield structure. The magnetic side shield has a flare angle that is greater than that of the write pole, and has a bevel angle that is smaller than that of the write pole. This advantageously provides a strong write field, while also preventing adjacent track and far track interference. The write head can include a bi-layer non-magnetic side gap structure, wherein one layer of the bi-layer side gap structure has a uniform thickness and the other layer has a non-uniform thickness.