DC Magnetic Profile Measuring Device Using AC Probe Modulation
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Solution Overview
Problem
Conventional magnetic force microscopes (MFM) face challenges in measuring direct-current (DC) magnetic fields due to weak signal intensity and poor signal-to-noise ratio, particularly in distinguishing perpendicular and in-plane magnetic field components.
Innovation Solution
A magnetic profile measuring technique using a probe on a driven cantilever, where an alternating-current magnetic field generator periodically reverses the probe's magnetization, allowing for frequency and amplitude modulation of the cantilever's vibration, enabling the separation of perpendicular and in-plane magnetic field components by adjusting the phase of the measurement signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MFM is used to measure DC magnetic field, then magnetic field distribution can be obtained, but signal intensity is weak and signal-to-noise ratio is poor
Solution Approach 1:
The patent applies periodic action by using an alternating-current magnetic field generator to periodically reverse the magnetization of the probe. This periodic reversal modulates the magnetic interaction force between the probe and specimen at a known frequency, enabling synchronous detection and significantly improving the signal-to-noise ratio while maintaining measurement precision of the DC magnetic field.
2Loss of information
If conventional MFM measures DC magnetic field, then magnetic profile can be obtained, but perpendicular and in-plane magnetic field components cannot be distinguished
Solution Approach 1:
The patent segments the magnetic field measurement by using the alternating-current magnetic field to selectively modulate specific magnetic field components. By controlling the phase and frequency of the alternating-current field, the measurement can be separated into perpendicular and in-plane components, allowing distinct imaging of each component without information loss or overlap.
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 technique allows for the accurate separation and imaging of perpendicular and in-plane magnetic field components, overcoming the limitations of overlapping magnetic field components in conventional MFM measurements.
Implementation Method 1
an alternating-current magnetic field generator for generating an alternating-current magnetic field and periodically reversing a magnetic polarity of the probe
Implementation Method 2
a magnetic signal which corresponds to an alternating magnetic force occurring between the probe and the specimen
Implementation Method 3
driving the cantilever at a resonant frequency of the cantilever or at a frequency close to the resonant frequency
Data Source
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AI summary
A magnetic profile measuring device which scans on a surface of a specimen by a magnetized probe on a tip of a driven cantilever, detects vibration of the cantilever, and generates a magnetic field distribution image of the area, the device including: the cantilever having the probe equipped on tip thereof; a driver driving the cantilever; an alternating-current magnetic field generator periodically reversing the magnetic polarity of the probe; a vibration sensor detecting vibration of the probe; a demodulator demodulating from a detection signal of the vibration sensor a magnetic signal corresponding to an alternating magnetic force between the probe and the specimen; a scanning mechanism; a data storage storing an initial data for each coordinate of the scanning area; a modified data generator generating a plurality of data by modifying the phase of the initial data; and an image display device.