Spin Hall Effect Magnetic Sensor Gap Thickness Reduction
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Solution Overview
Problem
Current magnetic sensors, such as GMR and TMR sensors, face limitations in reducing the read gap thickness due to the need for a pinned layer structure and antiferromagnetic material layers, which impede the reduction of bit length and data density in magnetic recording systems.
Innovation Solution
A magnetic sensor utilizing the spin Hall effect to polarize electrons, eliminating the need for a pinned layer structure and antiferromagnetic material layers by using a non-magnetic, electrically conductive layer adjacent to a magnetic free layer, which generates an electric potential in response to changes in magnetization, allowing for a thinner gap thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pinned layer structure with anti-parallel coupled magnetic layers and antiferromagnetic material layer is used, then magnetic sensor functionality is achieved, but gap thickness increases
Solution Approach 1:
The patent extracts and eliminates the pinned layer structure and antiferromagnetic material layer from the magnetic sensor design. By using spin-polarized electrons injected from a ferromagnetic layer to directly switch the magnetization of the free layer, the invention removes the need for the complex pinned layer structure, thereby reducing gap thickness while maintaining sensor functionality
Solution Approach 2:
The invention changes the operational mechanism from relying on pinned layer structure to utilizing spin-polarized electron injection. By changing the magnetization switching mechanism to depend on spin transfer torque from polarized electrons rather than exchange coupling with pinned layers, the gap thickness parameter can be reduced
2Productivity
If gap thickness is reduced to increase linear data density, then data density increases, but manufacturing precision requirements increase
Solution Approach 1:
By removing the pinned layer structure and antiferromagnetic layers, the invention reduces the number of layers that require precise thickness control and alignment. This simplification directly reduces manufacturing precision requirements while enabling thinner gap dimensions for higher data density
3Stability of the object's composition
If pinned layer structure is used, then magnetic layer stability is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the pinned layer structure and antiferromagnetic material layer from the device. By using spin-polarized electron injection to stabilize and switch the free layer magnetization, the invention reduces device complexity while maintaining magnetic layer stability through a different physical mechanism
Solution Approach 2:
The invention introduces spin-polarized electrons as an intermediary mechanism to achieve magnetic layer stability and switching. Instead of direct exchange coupling through pinned layers, the spin-polarized electrons act as a mediator to transfer angular momentum and stabilize the free layer magnetization
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 spin Hall effect-based sensor significantly reduces the gap thickness, enabling increased data density and eliminating issues related to pinning loss, thereby enhancing the recording capabilities of magnetic data storage systems.
Implementation Method 1
The non-magnetic, electrically conductive layer is configured to accumulate spin polarized electrons at a side thereof based on a spin Hall effect when an electrical current flows through the non-magnetic, electrically conductive layer
Implementation Method 2
This electrical potential varies in response to changes in the direction of magnetization of the magnetic free layer relative to the spin polarization of electrons in the nonmagnetic, electrically conductive layer
Data Source
AI summary
A magnetic sensor utilizing the spin Hall effect to polarize electrons for use in measuring a magnetic field. The sensor eliminates the need for a pinned layer structure or antiferromagnetic layer (AFM layer), thereby reducing gap thickness for increased data density. The sensor includes a non-magnetic, electrically conductive layer that is configured to accumulate electrons predominantly of one spin at a side thereof when a current flows there-through. A magnetic free layer is located adjacent to the side of the non-magnetic, electrically conductive layer. A change in the direction of magnetization in the free layer relative to the orientation of the spin polarized electrons causes a change in voltage output of the sensor.