Hybrid AMR PHR Sensor Detects Single Magnetic Particles at Room Temperature
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Solution Overview
Problem
Current magnetometry systems are limited by low working temperatures, complexity, and lack of portability, making them unsuitable for precise room temperature measurements of single nano-particles, and they struggle to detect nano or picotesla fields generated by small magnetic objects.
Innovation Solution
A micromagnetometry system using a hybrid AMR/PHR multi-ring sensor with a bi-layered or tri-layered magnetic track structure, capable of detecting stray magnetic fields from motionless particles at room temperature, employing a magnetic excitation field and differential voltage measurement to detect minimal magnetization shifts of 10 nT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional micro-SQUID technique is used, then magnetic detection sensitivity is improved, but working temperature is limited below few tens of Kelvin and device complexity increases
Solution Approach 1:
The patent changes the operating temperature parameter from cryogenic (micro-SQUID) to room temperature by using a different detection principle (magnetoresistive sensing instead of superconducting quantum interference), thereby resolving the temperature limitation while maintaining detection capability
Solution Approach 2:
The patent replaces the superconducting quantum interference mechanism with a magnetoresistive sensing mechanism, substituting a complex cryogenic system with a simpler room-temperature solid-state device that achieves comparable sensitivity
2Measurement precision
If conventional micro-SQUID technique is used, then magnetic detection sensitivity is improved, but device complexity increases and portability decreases
Solution Approach 1:
The patent replaces complex superconducting quantum interference devices with simpler magnetoresistive sensors that operate at room temperature, eliminating the need for cryogenic equipment and complex support systems, thereby reducing overall device complexity and improving portability
Solution Approach 2:
The patent employs solid-state magnetoresistive sensors that are simpler, more robust, and potentially disposable compared to fragile superconducting devices, reducing the need for complex support infrastructure and making the system more portable
3Measurement precision
If conventional micro-SQUID technique is used, then magnetic detection sensitivity is improved, but portability and flexibility decrease
Solution Approach 1:
The patent changes the operating conditions from cryogenic to room temperature, enabling portable and flexible applications while maintaining detection sensitivity through the use of magnetoresistive sensing technology
4Measurement precision
If magnetic excitation field is applied to detect single magnetic particles, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic magnetic excitation fields at specific frequencies to resonate with the magnetic particles, enhancing detection sensitivity through resonant effects while minimizing energy consumption by using brief, frequency-tuned pulses rather than continuous 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
Enables sensitive detection of single magnetic particles or objects at room temperature with improved portability and flexibility, achieving high sensitivity and minimal magnetization field detection thresholds.
Implementation Method 1
a first magnetic hybrid AMR/PHR multi-ring sensor having an active surface including a magnetic track
Implementation Method 2
a first magnetic hybrid AMR/PHR multi-ring sensor having an active surface including a magnetic track
Implementation Method 3
means for creating a magnetic excitation field H AC to make produce by each magnetic particle a stray magnetic field, the magnetic excitation field H AC oscillating along the time at a constant frequency ω
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A micromagnetometry system for detecting the presence of very small quantities of magnetic particles comprises a first magnetic hybrid AMR/PHR multi-ring sensor (4) using a Wheastone bridge electrical configuration, a first current source (6), a first voltage measurement device (8), a set of at least one magnetic particles (12) deposited on the first magnetic sensor (4) and a processing unit (22) for detecting from a set of different measured differential voltages a magnetic flux shift representative of the presence of a least one deposited magnetic particle (12). The micromagnetometry system comprises means (20) for creating a magnetic excitation field HAC to make produce by each motionless magnetic particle (12) a stray magnetic field oscillating along the time at a constant frequency w ranging from 10 Hz to 3 KHz.