Vortex Magnetoresistive Sensor With Passive Temperature Compensation
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Solution Overview
Problem
Magnetoresistive sensor elements face significant challenges in maintaining sensitivity and accuracy due to temperature-dependent variations in susceptibility and tunnel magnetoresistance, which require additional electronic circuits for compensation, increasing complexity and die size.
Innovation Solution
The magnetoresistive sensor element incorporates a sense layer with a stable vortex configuration and a tunnel barrier layer, where the second ferromagnetic sense portion includes a transition metal element in a specific proportion to compensate for the temperature dependence of magnetic susceptibility and tunnel magnetoresistance, thereby minimizing the temperature coefficient of sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional electronic circuits are added to compensate for temperature dependence, then sensitivity and accuracy are improved, but device complexity and die size increase
Solution Approach 1:
The patent applies the self-service principle by incorporating a temperature compensation layer directly into the magnetoresistive sensor element structure. This layer passively compensates for temperature-induced sensitivity variations through its inherent material properties, eliminating the need for external electronic compensation circuits. The sensor element becomes self-compensating, reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The patent employs composite materials by combining the ferromagnetic sense layer with a temperature compensation layer having specific magnetic and thermal properties. This composite structure allows the sensor to inherently compensate for temperature effects through the interaction between layers, providing both sensing and temperature compensation functions within a single integrated element without requiring additional electronic circuits.
2Measurement precision
If additional electronic circuits are added to compensate for temperature dependence, then sensitivity and accuracy are improved, but die size increases
Solution Approach 1:
The patent merges the temperature compensation function with the sensing element itself by integrating a temperature compensation layer into the magnetoresistive sensor structure. This consolidation allows both sensing and temperature compensation to occur within the same physical footprint, eliminating the need for separate compensation circuits and reducing overall die size while maintaining sensitivity.
3Stability of the object's composition
If vortex configuration is used in sense layer, then linear and non-hysteretic behavior is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the sense layer and the properties of the temperature compensation layer to enable spontaneous vortex formation. By adjusting these physical parameters during manufacturing, the process achieves stable vortex configuration and linear magnetic behavior without requiring excessively tight manufacturing tolerances, thus balancing performance with manufacturability.
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 results in a magnetoresistive sensor element with minimal temperature dependence of sensitivity, eliminating the need for additional electronic circuits and allowing for a smaller die size, thus simplifying the manufacturing process and enhancing sensing performance.
Implementation Method 1
the sense magnetization 210 comprises a stable vortex configuration having a core 213 reversibly movable in accordance to the external magnetic field 60
Implementation Method 2
a temperature dependence of a magnetic susceptibility of the sense layer substantially compensates a temperature dependence of a tunnel magnetoresistance
Implementation Method 3
measuring a resistance of the magnetoresistive sensor element 2. The resistance depends on the relative orientation of the sense magnetization and the reference magnetization
Implementation Method 4
the second ferromagnetic sense portion comprising a transition metal element in a proportion such that a temperature dependence of a magnetic susceptibility of the sense layer substantially compensates a temperature dependence of a tunnel magnetoresistance
Data Source
AI summary
A magnetoresistive sensor element including: a reference layer having a pinned reference magnetization; a sense layer having a free sense magnetization comprising a stable vortex configuration reversibly movable in accordance to an external magnetic field to be measured; a tunnel barrier layer between the reference layer and the sense layer; wherein the sense layer includes a first ferromagnetic sense portion in contact with the tunnel barrier layer and a second ferromagnetic sense portion in contact with the first ferromagnetic sense portion; the second ferromagnetic sense portion including a dilution element in a proportion such that a temperature dependence of a magnetic susceptibility of the sense layer substantially compensates a temperature dependence of a tunnel magnetoresistance of the magnetoresistive sensor element. Also, a method for manufacturing the magnetoresistive sensor element.