Antiparallel Write Head Pole Laminate for Magnetic Remanence
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Solution Overview
Problem
The existing write head pole structures for magnetic recording suffer from magnetic remanence issues, which can lead to data deterioration or erasure due to non-zero residual magnetic moments when the write current is removed, as the main pole's easy axis is not always oriented parallel to the air bearing surface.
Innovation Solution
A write head pole laminate structure is designed with multiple multi-layer magnetic structures separated by non-magnetic layers, where each multi-layer structure consists of antiparallel magnetic layers to achieve a close-to-zero total magnetic moment when the write head pole is not energized, utilizing amorphous or microcrystalline non-magnetic materials to break epitaxial grain growth and reduce surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional main pole structure is used, then the write head can generate a magnetic field for recording, but the residual magnetic moment does not return to zero when current is removed, causing data deterioration or erasure
Solution Approach 1:
The main pole is divided into multiple antiparallel magnetic layers (first magnetic layer and second magnetic layer) separated by a non-magnetic layer. Each layer can be independently magnetized in opposite directions, allowing their magnetic moments to cancel each other out and achieve near-zero remnant moment when write current is removed.
Solution Approach 2:
The patent uses antiparallel magnetic layers where the second magnetic layer is magnetized in the opposite direction to the first magnetic layer. These opposing magnetic moments act as counterweights that cancel each other out, eliminating the harmful remnant magnetic field that would otherwise deteriorate stored data.
2Object-generated harmful factors
If multiple antiparallel magnetic layers are used to reduce remanence, then magnetic remanence is minimized, but the device structure becomes more complex
Solution Approach 1:
The patent employs a composite structure consisting of multiple magnetic layers (soft magnetic material layers) separated by a non-magnetic layer. This composite architecture allows the combination of materials with different magnetic properties to achieve near-zero remnant moment while maintaining a manageable structural complexity through systematic layering.
3Power
If the easy axis of the main pole is oriented perpendicular to the air bearing surface, then strong write field is generated, but the residual magnetic moment has a perpendicular component that erases data
Solution Approach 1:
The patent inverts the conventional single-direction magnetization approach by using antiparallel magnetic layers. Instead of having all magnetic moments aligned perpendicular to the air bearing surface, the second magnetic layer is magnetized in the opposite direction, causing the perpendicular components to cancel out while maintaining the ability to generate strong write fields during operation.
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 effectively minimizes magnetic remanence, ensuring reliable data storage by maintaining a zero net magnetic moment when the write head is not active, thus preventing data loss and improving the magnetic properties of the write head pole.
Implementation Method 1
an electrical current is caused to flow through a conductive coil in the write head to induce a magnetic field across the gap between the main and return poles
Implementation Method 2
The main pole is generally made of a soft magnetic material that becomes magnetized in a direction perpendicular to the ABS, and generates a magnetic field in the media during recording
Implementation Method 3
utilizing amorphous or microcrystalline non-magnetic materials to break epitaxial grain growth and reduce surface roughness
Data Source
AI summary
The present invention generally relates to a write head pole laminate structure. The write head pole structure can include multiple multi-layer magnetic structures that are separated by a non-magnetic material that is amorphous or microcrystalline. Each multi-layer magnetic structure includes one or more first magnetic layers that are spaced from one or more second magnetic layers by a non-magnetic layer such that the one or more first magnetic layers are substantially identical to the one or more second magnetic layers. In such a design, the one or more second magnetic layers are antiparallel to the one or more first magnetic layers so that a zero total net magnetic moment is present for the multi-layer magnetic structure when current is removed from the write head pole.