Wide Conductive Layer in Magnetic Write Gap for Current-Assisted Switching
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Solution Overview
Problem
Current-assisted write heads in magnetic recording systems face challenges in fabrication due to the requirement of a separate electrical coil and current path, leading to issues like current crowding and corrosion near the write pole, which affect the magnetization switching speed and increase the soft error rate.
Innovation Solution
A non-magnetic electrically conductive layer is introduced in the write gap between the write pole and the trailing shield, with a wide cross-track width to reduce electrical resistance and spread current to the side shields and trailing shield, minimizing hot spots and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a separate electrical coil and current path are used in current-assisted write heads, then magnetization switching speed can be improved, but fabrication difficulty increases and current crowding occurs leading to corrosion
Solution Approach 1:
The patent combines the auxiliary coil and current path functions into the write pole structure itself. The write pole serves dual purposes: generating the main write field through write current and providing the current path for auxiliary current that generates the transverse magnetic field for magnetization switching assistance. This integration eliminates the need for separate auxiliary coils and reduces fabrication complexity.
Solution Approach 2:
The write pole is designed to perform multiple functions: it generates the primary write magnetic field through write current flow, and simultaneously serves as the current path for auxiliary current that produces a transverse magnetic field component. This multi-functionality reduces the number of separate components needed and simplifies the overall head structure.
2Speed
If a separate electrical coil and current path are used in current-assisted write heads, then magnetization switching speed can be improved, but corrosion near the write pole occurs
Solution Approach 1:
By integrating the auxiliary current path into the write pole structure rather than using separate components, the patent reduces the number of interfaces and contact points where current crowding can occur. The unified structure minimizes localized heating and corrosion risks while maintaining the magnetization switching assistance function.
3Ease of manufacture
If conventional write head design is used, then fabrication is simpler, but magnetization switching speed is limited at high data rates
Solution Approach 1:
The patent modifies the magnetic field generation mechanism by introducing auxiliary current flow through the write pole, which creates a transverse magnetic field component. This changes the magnetization switching mechanism from relying solely on longitudinal field reversal to utilizing torque-assisted switching, thereby improving switching speed while maintaining compatibility with existing fabrication processes.
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 magnetization switching speed, reduces soft error rates, and increases disk areal data density by distributing current effectively, while preventing corrosion and improving write field gradient.
Implementation Method 1
The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetic flux in the write pole to assist magnetization switching of the write pole
Implementation Method 2
Electrical circuitry directs current between the write pole and the trailing shield, through the conductive layer in the write gap
Data Source
AI summary
A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current between the write pole and the trailing shield, through the conductive layer in the write gap. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The conductive layer is wider in the cross-track direction than the trailing edge of the write pole and may extend beyond the write pole side gaps so as to be in contact with both the side shields and the trailing shield. The conductive layer may have substantially the same along-the-track thickness across its width or it may have a thicker central region at the write pole trailing edge and thinner side regions.