Magnetoresistive Sensor Element With Diluted Sense-Layer Compensation
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Solution Overview
Problem
Existing magnetoresistive sensors face significant challenges due to the temperature-dependent variation in sensitivity (TCS) that affect their performance and application range, necessitating complex electronic circuits for compensation, which increase die size and development complexity.
Innovation Solution
A magnetoresistive sensor element with a ferromagnetic sense layer containing a transition metal element in a specific proportion to compensate for the temperature dependence of susceptibility and tunnel magnetoresistance, eliminating the need for additional electronics and allowing for a smaller die size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex electronic circuits are used to compensate for temperature dependence of sensitivity, then temperature stability is improved, but device complexity and die size increase
Solution Approach 1:
The patent extracts the temperature compensation function from external electronic circuits and integrates it into the magnetoresistive sensor element itself through the second ferromagnetic sense portion. This eliminates the need for separate compensation circuits while maintaining temperature stability.
Solution Approach 2:
The patent merges the sensing function and temperature compensation function into a single integrated structure. The second ferromagnetic sense portion is coupled to both the tunnel barrier layer (for sensing) and configured to compensate temperature dependence (for stability), combining multiple functions in one component.
2Reliability
If complex electronic circuits are used to compensate for temperature dependence of sensitivity, then temperature stability is improved, but die size increases
Solution Approach 1:
The patent removes the need for external temperature compensation circuits, thereby eliminating the additional die area they would occupy. The compensation function is extracted and embedded within the sensor element's magnetic layer structure.
Solution Approach 2:
By merging the compensation function into the existing sensor structure, the patent avoids adding separate compensation circuitry that would increase die size. The second ferromagnetic sense portion serves dual purposes: sensing and temperature compensation.
3Reliability
If additional electronics are added for temperature compensation, then sensitivity consistency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the temperature compensation function from external electronics and embeds it in the magnetic layer structure, which can be manufactured using standard thin-film deposition techniques already employed in magnetoresistive sensor fabrication.
Solution Approach 2:
The patent combines the compensation function with the sensing structure, allowing both to be fabricated in the same manufacturing process sequence without requiring additional electronics assembly or testing steps.
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 minimal temperature dependence of sensitivity, ensuring consistent performance across varying temperatures without additional electronics, thus simplifying manufacturing and reducing die size.
Implementation Method 1
The resistance depends on the relative orientation of the sense magnetization and the reference magnetization
Implementation Method 2
a ferromagnetic reference layer 23 including a first ferromagnetic layer 231 having a first reference magnetization 234 and a second ferromagnetic layer 232 having a second reference magnetization 235
Data Source
Figure 1~2b
Figure 3~4b
Figure 5~6(c)
AI summary
The present disclosure concerns a magnetoresistive sensor element (2) comprising: a reference layer (23) having a pinned reference magnetization (230); a sense layer (21) having a free sense magnetization (210) comprising a stable vortex configuration reversibly movable in accordance to an external magnetic field (60) to be measured; a tunnel barrier layer (22) between the reference layer (23) and the sense layer (21); wherein the sense layer (21) comprises a first ferromagnetic sense portion (211) in contact with the tunnel barrier layer (22) and a second ferromagnetic sense portion (212) in contact with the first ferromagnetic sense portion (211); the second ferromagnetic sense portion (212) comprising a dilution element in a proportion such that a temperature dependence of a magnetic susceptibility (χ) of the sense layer (21) substantially compensates a temperature dependence of a tunnel magnetoresistance of the magnetoresistive sensor element. The present disclosure concerns a method for manufacturing the magnetoresistive sensor element.