MAMR Head Side Gap Structure for STO Oscillation Stability
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Solution Overview
Problem
The miniaturization of components in magnetic hard disk drives (HDDs) for higher recording density is hindered by the difficulty in positioning spin torque oscillators (STOs) and main poles, leading to instability in the high-frequency magnetic field and reduced manufacturing yield due to variations in width and positional relationships during the manufacturing process.
Innovation Solution
A microwave-assisted magnetic recording (MAMR) head design that includes a main pole, a trailing shield, a spin torque oscillator (STO) positioned between them, and electrically conductive and insulating non-magnetic bodies on the sides of the main pole and STO, ensuring stable oscillation and high-frequency magnetic field generation regardless of STO width variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the STO width is reduced to improve positioning precision and manufacturing yield, then the positioning precision improves, but the high-frequency magnetic field intensity decreases
Solution Approach 1:
The patent applies local quality by creating a non-uniform current density distribution through the side gap structure. The side gap is positioned closer to the STO at its center than at its edges, causing current to concentrate at the STO edges where it is needed most for generating the high-frequency magnetic field. This localized current enhancement compensates for the reduced STO width while maintaining positioning precision.
2Manufacturing precision
If the STO width is reduced to improve positioning precision, then the positioning precision improves, but the oscillation stability deteriorates
Solution Approach 1:
The side gap structure creates localized current concentration at the STO edges through varying gap distances. This non-uniform current distribution stabilizes the oscillation by ensuring adequate current density at the critical edge regions of the STO, even when the overall STO width is reduced for better positioning precision.
3Power
If the STO width is increased to improve high-frequency magnetic field intensity, then the magnetic field intensity improves, but the positioning precision and manufacturing yield deteriorate
Solution Approach 1:
The patent changes the geometric parameter of the side gap structure, specifically the distance between the side gap and the STO at different positions. By making the side gap closer to the STO at the center than at the edges, the current density is redistributed to enhance the magnetic field intensity without increasing the STO width, thus maintaining positioning precision and manufacturing yield.
4Stability of the object's composition
If the STO width is increased to improve oscillation stability, then the oscillation stability improves, but the positioning precision and manufacturing yield deteriorate
Solution Approach 1:
The patent modifies the side gap geometric parameters to create a non-uniform structure where the gap distance varies across the STO width. This parameter change enables stable oscillation through optimized current distribution at the STO edges without requiring an increased STO width, thereby preserving positioning precision and manufacturing yield.
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 the stability and frequency of oscillation, improving recording density and manufacturing ease by ensuring consistent current distribution and magnetic field intensity across the STO, leading to improved surface recording density and manufacturing yield.
Implementation Method 1
STOs are able to generate a minute high-frequency vibrating magnetic field by injecting conduction electrons with spin fluctuations generated by a GMR structure into a magnetic body by way of a non-magnetic body
Implementation Method 2
a circuit adapted to flow an electric current therethrough to the main pole, the oscillation device, and the trailing shield
Implementation Method 3
a high-frequency magnetic field of a strong microwave band across a nanometer-order region to locally excite the recording medium within this region and reduce the magnetization-reversing magnetic field
Data Source
AI summary
A microwave-assisted magnetic recording (MAMR) head according to one embodiment includes a main pole; a trailing shield positioned downstream from the main pole; an oscillation device adapted to generate a high-frequency magnetic field, the oscillation device being positioned between the main pole and the trailing shield; a circuit adapted to flow an electric current therethrough to the main pole, the oscillation device, and the trailing shield; an electrically conductive non-magnetic body positioned on one or more sides of the main pole in a cross-track direction and/or a leading direction; and an insulating non-magnetic body positioned on one or more sides of the electrically conductive non-magnetic body in the cross-track direction and/or the leading direction, wherein one or more edge portions of one side of the oscillation device and one or more edge portions of one side of the main pole are in direct contact with the electrically conductive non-magnetic body.