Magnetic Sensor Eliminating Bias Layer for Hysteresis Stability
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Solution Overview
Problem
Magnetic sensors with bias layers suffer from deteriorated hysteresis and linearity when exposed to strong magnetic fields, as the magnetization of the bias layer is easily fluctuated, leading to changes in output and sensitivity issues.
Innovation Solution
The magnetic sensor design eliminates the bias layer and features an electrode layer on the upper surface of element sections, with a laminated structure of fixed and free magnetic layers, allowing for shape anisotropy effects that stabilize magnetization direction and improve hysteresis and linearity, even under strong magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bias layer is used to supply bias magnetic field to element sections, then magnetic field detection capability is improved, but hysteresis and linearity deteriorate when exposed to strong magnetic fields due to magnetization fluctuation of the bias layer
Solution Approach 1:
The invention removes the bias layer from the magnetic sensor structure, extracting the problematic component that caused magnetization fluctuation under strong magnetic fields. This elimination resolves the contradiction by maintaining detection capability through alternative means (electrode layer configuration and shape anisotropy) while eliminating the source of hysteresis and linearity deterioration.
Solution Approach 2:
The invention applies local quality by creating specific regions with different properties: electrode layers are positioned only on upper surfaces of element sections that face joint sections, creating non-sensitive regions that prevent sensitivity deterioration while maintaining detection capability in other areas. This localized electrode arrangement improves reliability without sacrificing measurement precision.
2Stability of the object's composition
If the element section is made long in the X1-X2 direction without bias layer, then shape anisotropy effect is improved and magnetization direction is stabilized, but device complexity increases due to electrode layer arrangement
Solution Approach 1:
The invention segments the electrode layer arrangement by positioning electrodes only on specific upper surfaces of element sections that face joint sections, rather than uniformly across all surfaces. This segmented approach achieves the necessary magnetization stabilization through shape anisotropy while minimizing device complexity by avoiding unnecessary electrode structures in non-critical areas.
Solution Approach 2:
The invention utilizes the vertical dimension (thickness direction) for electrode layer placement on upper surfaces, rather than attempting to manage complexity through planar arrangements. This dimensional approach allows simple electrode configuration to achieve the desired magnetic field tolerance and magnetization stability without increasing overall device 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
This configuration enhances the tolerance to strong magnetic fields and improves hysteresis and linearity properties, maintaining stability and sensitivity in magnetic field detection.
Implementation Method 1
the element section is formed in a long shape in the X1-X2 direction without using a bias layer, thus the element section can be arranged other than magnetic field detection, and it is possible to appropriately obtain the shape anisotropy effect
Implementation Method 2
A magnetic sensor using magneto-resistive sensors can be used as, for example, a terrestrial magnetic sensor which detects terrestrial magnetism
Data Source
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AI summary
A magnetic sensor includes a non-bias structured element section (9) that has a laminated structure in which a fixed magnetic layer (61), a non-magnetic material layer (62), a free magnetic layer (63), and a protection layer (64) are laminated, and that is extended in an X1-X2 direction; and a plurality of soft magnetic bodies (12,14) that are arranged on the element section (9) in a contactless manner. Each of the soft magnetic bodies (12,14) includes a first section (12e,14e), a second section (12f), and a third section (12g). The second section (12f) is located on a Y2 side of the element section (9) and the third section (12g) is located on a Y1 side of the element section (9). The second section (12f) of one of adjacent soft magnetic bodies (12,14) faces the third section (12g) of the other soft magnetic body (12, 14) in a Y1-Y2 direction through the element section (9). An electrode layer (16) which biases current is provided on the element section (9) which faces the joint sections (12f1,12g1) of the second section (12f) and the third section (12g) in the Y1-Y2 direction.