Study on Detection of a Small Magnetic Particle Using Thin Film Magneto-Impedance Sensor with Subjecting to Strong...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thin film magneto-impedance (MI) sensors exhibit high sensitivity (pico-tesla order) at high frequencies (hundreds of MHz).
• Detecting small, low-remanence magnetic particles or nano-particle clusters poses a significant challenge.

Purpose of the Study:

• To propose and validate a sensitive measurement method for detecting small magnetic particles or nano-particle clusters.
• To investigate the effect of a strong external normal magnetic field on MI sensor performance.

Main Methods:

• Fabrication of a soft magnetic amorphous thin-film MI sensor with specific magnetic anisotropy.
• Application of a strong external normal magnetic field (hundreds of mT) perpendicular to the sensor plane.
• Theoretical estimation and experimental validation of sensor properties and sensitivity under the applied field.

Main Results:

• The proposed method maintains high sensor sensitivity despite the strong external normal field, attributed to demagnetizing forces.
• Experimental results confirm the sensor's property and sensitivity under the normal field.
• Successful detection of a small particle using the developed method was demonstrated.

Conclusions:

• A strong normal magnetic field can be effectively utilized to enhance the detection sensitivity of magneto-impedance sensors for small magnetic objects.
• The method shows promise for applications requiring the detection of nano-scale magnetic entities.
• Further discussion covers detection principles with field distribution and particle movement.