Strain Sensing Element With Bias Layers For Demagnetizing Field Suppression
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Solution Overview
Problem
Current strain sensing elements using spin technology face challenges in achieving high sensitivity due to limitations in materials and structural design, particularly in suppressing demagnetizing fields and optimizing magnetic field application.
Innovation Solution
A strain sensing element is designed with a deformable film unit and bias layers, including magnetic body layers and intermediate magnetic layers, arranged in specific directions to enhance the magnetoresistance effect and suppress demagnetizing fields, thereby improving sensitivity and gauge factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spin technology is used for strain sensing element, then sensitivity can be improved, but demagnetizing fields cause measurement precision degradation
Solution Approach 1:
A non-magnetic intermediate layer is introduced between the magnetic body layer and the strain sensing element. This intermediate layer acts as a mediator that prevents direct magnetic interaction, thereby suppressing demagnetizing fields while preserving the magnetoresistance effect for strain sensing. The intermediate layer isolates the magnetic components from the sensing element, eliminating harmful magnetic field interference.
Solution Approach 2:
The harmful demagnetizing field effect is extracted and isolated from the strain sensing element by placing magnetic body layers at opposite ends of the sensing element. This configuration removes the magnetic interference from the central sensing region, allowing the strain sensing element to operate without demagnetizing field impact while still utilizing spin technology for high sensitivity.
2Measurement precision
If magnetic body layers are added to apply bias magnetic field, then strain sensing capability is enhanced, but device complexity increases
Solution Approach 1:
The magnetic body layers serve multiple functions simultaneously: they provide the bias magnetic field necessary for the magnetoresistance effect, and they are positioned to suppress demagnetizing fields. This multi-functionality enhances strain sensing capability without proportionally increasing device complexity, as the same structural elements perform both magnetic field application and interference suppression.
Solution Approach 2:
Magnetic body layers are strategically positioned only at specific locations (opposite ends of the strain sensing element) where they are most effective for applying bias magnetic field and suppressing demagnetizing fields. This localized approach enhances sensing capability in critical regions without adding magnetic components throughout the entire device, thereby controlling overall structural complexity.
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 solution achieves high sensitivity and a high gauge factor by effectively applying a bias magnetic field to the strain sensor, reducing the impact of demagnetizing fields and enhancing the strain sensing capability.
Implementation Method 1
An electrical characteristic of the strain sensor changes according to a deformation of the film unit
Implementation Method 2
bias layers, including magnetic body layers and intermediate magnetic layers, arranged in specific directions to enhance the magnetoresistance effect and suppress demagnetizing fields
Data Source
AI summary
According to one embodiment, a strain sensing element includes a film unit being deformable, a first and a second magnetic unit, and a strain sensor. The first magnetic unit is provided on the film unit and is arranged with the film unit in a first direction. The first magnetic unit includes a first magnetic body layer and a first intermediate magnetic layer. The second magnetic unit is provided on the film unit and is arranged with the first magnetic unit in a second direction crossing the first direction. The second magnetic unit includes a second magnetic body layer and a second intermediate magnetic layer. The strain sensor is provided on the film unit between the first magnetic unit and the second magnetic unit. An electrical characteristic of the strain sensor changes according to a deformation of the film unit.