Magnetic Sensor 1/f Noise Reduction via Magnetic Saturation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic sensors with magnetoresistance effect elements face challenges in accurately measuring small magnetic fields due to 1/f noise, which cannot be effectively removed by existing filtering methods.
Innovation Solution
A magnetic sensor configuration that includes a magnetoresistance effect element with a pinned and free magnetic layer, along with a saturation magnetic field application unit, allows for the calculation of a measurement magnetic field by subtracting 1/f noise from the sensor output using a difference between outputs with and without magnetic saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filtering methods are used to remove noise, then noise reduction is achieved, but 1/f noise cannot be effectively removed
Solution Approach 1:
The patent applies a saturation magnetic field to the free magnetic layer before measurement to preliminarily magnetize it. This preliminary action changes the magnetic state of the free layer, enabling the subsequent measurement to be less affected by 1/f noise while maintaining measurement accuracy
2Difficulty of detecting and measuring
If magnetoresistance effect elements are used for magnetic field detection, then magnetic field detection capability is achieved, but 1/f noise reduces detection accuracy
Solution Approach 1:
The patent changes the magnetic state parameter of the free magnetic layer by applying a saturation magnetic field. This parameter change transforms the magnetic layer from an unsaturated state to a saturated state, which alters the noise characteristics and improves detection accuracy for small magnetic fields
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 approach enables the removal of 1/f noise, thereby enhancing the accuracy of magnetic field measurements, particularly for small magnetic fields, and improving the overall magnetic resolution of the sensor.
Implementation Method 1
Some magnetic sensors for detecting and measuring magnetic fields include a magnetoresistance effect element that uses the giant magnetoresistance (GMR) effect or the tunnel magnetoresistance (TMR) effect
Implementation Method 2
Some magnetic sensors for detecting and measuring magnetic fields include a magnetoresistance effect element that uses the giant magnetoresistance (GMR) effect or the tunnel magnetoresistance (TMR) effect
Implementation Method 3
a saturation magnetic field application unit configured to apply a magnetic field to the free magnetic layer in a direction of the measurement magnetic field to magnetically saturate the free magnetic layer
Data Source
AI summary
A magnetic sensor includes a magnetic detection unit including a magnetoresistance effect element having a pinned magnetic layer, a free magnetic layer, and an intermediate layer formed between the pinned magnetic layer and the free magnetic layer, a magnetic field calculation unit configured to calculate a measurement magnetic field based on an output of the magnetic detection unit, and a saturation magnetic field application unit configured to apply a magnetic field to the free magnetic layer in a direction of the measurement magnetic field to magnetically saturate the free magnetic layer. The magnetic field calculation unit calculates the measurement magnetic field based on a first output of the magnetic detection unit when the measurement magnetic field is applied to the free magnetic layer, and a second output of the magnetic detection unit when the free magnetic layer is magnetically saturated.