Spin Hall Magnetic Sensor Layout for SOT Signal Sensitivity
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Solution Overview
Problem
Existing magnetic sensors using the Wheatstone bridge structure for detecting magnetic fields suffer from limited sensitivity due to the cancellation of Hall resistance components generated by spin orbit torque (SOT), necessitating improvements in signal detection and sensitivity.
Innovation Solution
A magnetic sensor design incorporating a multilayer structure with specific angular configurations of magnetic and non-magnetic thin film units, utilizing a Wheatstone bridge structure to isolate and enhance the magnetic resistance component generated by SOT, and applying an AC current to detect secondary harmonic signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Wheatstone bridge structure is used to detect magnetic fields, then the structure can detect changes in resistance, but the sensitivity is limited due to cancellation of Hall resistance components generated by spin orbit torque
Solution Approach 1:
The patent introduces magnetic thin film units with specific angular orientations (45°, 135°, 225°, 315°) relative to the current direction, creating an asymmetric configuration that prevents cancellation of Hall resistance components while maintaining Wheatstone bridge structure. This asymmetric angular arrangement ensures that all units contribute constructively to the output signal.
Solution Approach 2:
Each magnetic thin film unit is configured with a specific longitudinal direction angle relative to the current input direction. This local variation in orientation (45°, 135°, 225°, 315°) optimizes the Hall resistance generation at each position while maintaining overall bridge balance, thereby enhancing sensitivity without requiring structural asymmetry at the macro level.
2Measurement precision
If multiple magnetic thin film units are arranged in a Wheatstone bridge structure, then the sensor can measure magnetic resistance, but the device complexity increases
Solution Approach 1:
The patent uses identical magnetic thin film unit structures for all four positions in the Wheatstone bridge, with each unit serving multiple functions: detecting Hall resistance, contributing to bridge balance, and providing angular-dependent sensitivity. This universal design simplifies manufacturing while achieving enhanced measurement precision.
Solution Approach 2:
The sensor is divided into four discrete magnetic thin film units arranged in a Wheatstone bridge configuration, allowing independent optimization of each unit's angular orientation. This segmentation enables precise control over the magnetic response while maintaining a relatively simple overall structure that can be fabricated using standard thin-film deposition techniques.
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 proposed design achieves higher sensitivity by isolating and amplifying the magnetic resistance component generated by SOT, thereby improving signal detection and reducing noise, enhancing the sensor's performance.
Implementation Method 1
when a charge current is injected from the outside, a spin current is generated in the non-magnetic layer by the spin Hall effect, and the spin current is transmitted to an adjacent magnetic layer to generate a spin-orbit torque (SOT)
Data Source
AI summary
A spin Hall magnetic sensor includes a plurality of magnetic thin film units including a magnetic layer stacked on a non-magnetic layer, and a plurality of non-magnetic substances disposed between the plurality of magnetic thin film units, The magnetic includes a Wheatstone bridge structure to observe a magnetic Hall resistance generated by a spin orbit torque (SOT).