Characterizing Complex Mineral Structures in Thin Sections of Geological Samples with a Scanning Hall Effect...

Area of Science:

• Geophysics
• Materials Science
• Mineralogy

Background:

• Accurate measurement of magnetic properties in geological samples is crucial for understanding Earth's processes.
• Existing techniques may lack the spatial resolution or sensitivity required for detailed mineral analysis.

Purpose of the Study:

• To develop and validate an improved magnetic scanning microscope for submillimeter-scale analysis of mineral magnetic properties.
• To enhance spatial resolution and sensitivity for geological sample characterization.

Main Methods:

• Utilized a 200 µm Hall sensor positioned 142 µm from the sample.
• Incorporated a gradiometric Hall sensor configuration to minimize background noise and electromagnet interference.
• Employed a custom electronics system and a scanning XY stage for precise sample positioning and measurement.
• Applied an alternative model considering sample geometry for magnetization analysis.

Main Results:

• Achieved a spatial resolution of 200 µm with a noise level of 300 nT_rms/(Hz)^1/2 at 6.0 Hz in an unshielded environment.
• Demonstrated a magnetic moment sensitivity of 1.3 × 10^-11 Am².
• Successfully measured representative magnetization and identified micrometric characteristics in a geological sample slice.

Conclusions:

• The improved magnetic scanning microscope provides high-resolution and sensitive measurements of mineral magnetic properties.
• The system is effective for characterizing geological samples at the submillimeter scale.
• The developed methodology enables detailed analysis of magnetic features within mineral samples.