Narrow Spin Polarization Layer Write Head Design
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Solution Overview
Problem
Energy-assisted magnetic recording write heads require high voltage and current to achieve write field enhancement, which can degrade components and impact the lifetime and reliability of the write head.
Innovation Solution
A write head design featuring a narrow spin polarization layer and a wide spacer layer, with a wide seed or capping layer to reduce parasitic resistance, allowing for high current density and efficient spin torque operation with lower bias voltage, thereby enhancing spin torque efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage and high current are applied to produce write field enhancement in energy-assisted recording, then the write field enhancement is achieved, but the lifetime and reliability of the write head deteriorate due to component degradation
Solution Approach 1:
The patent changes the structural parameters of the spintronic device by narrowing the spin polarization layer width and increasing the spacer layer width. This parameter optimization enables the device to achieve the same spin torque effect with lower current density, thereby reducing the voltage and current requirements while maintaining write field enhancement capability and improving write head reliability
Solution Approach 2:
The patent applies different width dimensions to different layers locally - the spin polarization layer is narrowed to reduce resistance and improve spin polarization efficiency, while the spacer layer is widened to reduce parasitic resistance. This local quality differentiation allows the device to operate efficiently at lower power levels
2Manufacturing precision
If the main pole surface area is decreased to narrow write tracks for higher recording density, then recording density is improved, but the writing field strength is reduced
Solution Approach 1:
The patent introduces a spintronic device as an intermediary between the main pole and trailing shield. This device generates spin torque that produces an assisting magnetic field, effectively amplifying the writing field strength without requiring a larger main pole, thus enabling high recording density while maintaining sufficient write field
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 achieves lower bias voltage and higher spin torque efficiency, reducing the coercive force of the magnetic recording medium and allowing for smaller write fields, thus improving recording density without compromising the write head's reliability.
Implementation Method 1
charge current through a spin Hall layer generates a spin current in the spin Hall layer
Implementation Method 2
The spin orbital coupling of the spin Hall layer and a spin torque layer (STL) causes switching or precession of magnetization
Implementation Method 3
Transmitted polarized electrons from a spin polarization layer (SPL) and/or from reflected electrons are injected into the field generation layer causing switching or precession of the magnetization of the field generation layer by spin transfer torque
Implementation Method 4
from reflected electrons
Data Source
AI summary
In one embodiment, a write head includes a spin polarization layer (SPL) over a seed layer. A spacer layer is over the SPL. A trailing shield is over the spacer layer. The spacer layer forms a first interface between the spacer layer and the trailing shield and forms a second interface between the spacer layer and the SPL. The first interface has an area larger than an area of the second interface. In another embodiment, a write head includes a SPL over a spacer layer. A capping layer is over the SPL. A trailing shield is over the capping layer. The spacer layer forms a first interface between the spacer layer and the main pole and forms a second interface between the spacer layer and the SPL. The first interface has an area larger than an area of the second interface.