Magnetic Sensor Vortex Stability via Flux Concentrator
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Solution Overview
Problem
Magnetic xMR sensors face challenges in achieving reliable and accurate measurements due to hysteresis behavior caused by perturbations in magnetic fields, especially when the vortex magnetization state is unstable across varying field strengths.
Innovation Solution
A magnetic sensor device with a magneto-resistive structure featuring a magnetic free layer in a vortex configuration and a magnetic flux concentrator to increase the flux density of external magnetic fields, ensuring the vortex state remains stable and sensitive across a wider range of field strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vortex magnetization state is used in the free layer, then hysteresis is reduced to nearly zero, but the vortex state becomes unstable outside a certain range of field strength
Solution Approach 1:
A magnetic flux concentrator is introduced as an intermediary component between the external magnetic field and the free layer. This flux concentrator modifies and concentrates the magnetic flux, enabling the vortex state to remain stable across a broader range of external field strengths while preserving the low-hysteresis characteristic. The flux concentrator acts as a mediator that decouples the direct relationship between external field and vortex stability.
Solution Approach 2:
The invention changes the magnetic flux density parameter by introducing a flux concentrator with specific geometric parameters (size, shape, position). By adjusting these parameters, the local magnetic flux density in the free layer is modified, allowing the vortex state to maintain stability over a wider range of external field strengths while preserving low hysteresis.
2Measurement precision
If the vortex formation range is limited, then the sensor operates accurately within that range, but the sensor cannot reliably measure fields outside this range
Solution Approach 1:
The magnetic flux concentrator serves as a mediator that transforms external magnetic fields of various strengths into a controlled local flux density within the free layer. This allows the sensor to maintain accurate measurement across a broader external field range by confining the vortex state stability to the localized region influenced by the flux concentrator.
Solution Approach 2:
The flux concentrator introduces a spatial dimension to field control by creating a localized high-flux-density region. This spatial confinement allows the sensor to handle a broader range of external field strengths while maintaining vortex stability within the concentrated flux region, effectively extending the measurement range.
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 significantly reduces hysteresis and enhances the sensitivity of magnetic field sensors, maintaining accuracy and reliability even under varying magnetic conditions, making it suitable for applications like wheel speed sensing and current sensing.
Implementation Method 1
a magnetic flux concentrator configured to increase a flux density of an external magnetic field in the magnetic free layer
Implementation Method 2
Magneto-resistive effects include a number of different physical phenomena, all of which having in common that an electrical resistance of a resistive element is alterable by the behavior of a magnetic field penetrating the resistive element
Data Source
AI summary
The present disclosure relates to a magnetic sensor device having at least one magneto-resistive structure. The magneto-resistive structure comprises a magnetic free layer configured to generate a closed flux magnetization pattern in the free layer, and a magnetic reference layer having non-closed flux reference magnetization pattern; and a magnetic flux concentrator configured to increase a flux density of an external magnetic field in the magnetic free layer.