Hybrid AMR/PHR Magnetic Sensor for Low Power Field Detection
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Solution Overview
Problem
Existing magnetic Hall sensors require high power for operation, making them unsuitable for low power portable applications, and they are not effective at low temperatures, limiting their use in detecting small magnetic fields and variations generated by magnetic sources or particles.
Innovation Solution
A magnetic hybrid AMR/PHR sensing device with a magnetic field receiver and transmitter, configured with specific track shapes and materials, and aligned using an insulating spacer to optimize sensitivity and reduce power consumption, allowing for low power operation and detection of small magnetic fields across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall Magnetoresistive sensors are used to detect magnetic fields, then measurement sensitivity is improved, but power consumption increases
Solution Approach 1:
The patent combines AMR and PHR sensor structures into a hybrid configuration where magnetoresistive tracks are arranged with specific easy and hard axes orientations. This merging of two magnetic sensing mechanisms (AMR for longitudinal magnetization detection and PHR for transverse magnetization detection) enables the system to achieve high sensitivity for both in-plane and out-of-plane magnetic field components while reducing the need for high power external biasing fields that would otherwise be required by conventional Hall sensors
2Measurement precision
If external biasing fields are applied to Hall sensors, then measurement sensitivity is improved, but device complexity and power requirements increase
Solution Approach 1:
The hybrid AMR/PHR sensor structure is designed to utilize the magnetoresistive properties of the tracks themselves to provide the necessary magnetic sensing capability without requiring external biasing fields. The easy axis and hard axis orientations of the magnetoresistive tracks create intrinsic magnetic anisotropy that enables the sensor to operate autonomously, detecting magnetic fields through changes in electrical resistance along different axes without needing additional external magnetic field sources or complex biasing circuitry
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 device achieves high sensitivity in detecting local magnetic fields with reduced power consumption, enabling portable and low-temperature operation, suitable for applications such as detecting magnetic particles and fields without the need for external biasing currents, thus overcoming the limitations of existing sensors.
Implementation Method 1
Planar Hall Magnetoresistive (PHR) sensors are Anisotropic Magneto Resistance (AMR) coupled with planar Hall effect (PHE) sensors
Implementation Method 2
a first magnetic field transmitter as a second component, configured for being excited by a DC and/or AC supplied bias current or by an external magnetic field to be measured
Implementation Method 3
Anisotropic Magneto Resistance (AMR) coupled with planar Hall effect (PHE) sensors
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A
AI summary
A magnetic hybrid AMR/PHR based sensing device comprises a magnetic field receiver (4) having a magnetic hybrid AMR/PHR sensor and a first magnetic field transmitter (6) having a magneto-resistive or low resistive second track with a closed loop shape or a cross junction shape. The magnetic field receiver (4) and the magnetic field transmitter (6) are superimposed, secured to and separated by a first insulating spacer (62) configured to align respectively the first easy axis (18) and the first hard axis t(28) to the second easy axis (48) and the second hard axis (58), then rotate the said second axis (48, 58) from the said first axis (18, 18) at a predetermined fixed offset angle α , and to maintain this axis arrangement as well as a fixed separation distance e12 between the first track (10) and the second track (40) in a range from few micrometers to few nanometers.