Precision magnetometry at cryogenic temperatures with gaseous 3He NMR probes

Area of Science:

• Physics
• Materials Science
• Physical Chemistry

Background:

• Precision magnetometry is crucial for various scientific and technological applications.
• Existing methods for measuring weak magnetic fields can be complex or limited in scope.
• Helium-3 (3He) offers unique properties for sensitive magnetic field detection.

Purpose of the Study:

• To develop compact, gaseous 3He Nuclear Magnetic Resonance (NMR) probes for precision magnetometry.
• To enable measurements of magnetic fields (B) greater than 0.1 Tesla (T).
• To operate these probes across a wide temperature range, from ambient down to 4 Kelvin (K).

Main Methods:

• Utilizing gaseous 3He polarized at thermal equilibrium under high pressures (up to 100 bars) for high nuclear spin density.
• Incorporating paramagnetic substances and/or silica gel to reduce T1 relaxation times and achieve thermal polarization equilibrium.
• Employing single-pulse NMR measurements for sensor readout at rates of approximately Hertz (Hz).

Main Results:

• Demonstrated compact 3He NMR probes capable of precision magnetometry.
• Achieved operation from room temperature down to 4 K.
• Reached sensitivity limits in the range of 10^-11 < δB/B < 10^-7, improvable with signal averaging.

Conclusions:

• Compact gaseous 3He NMR probes are effective for precision magnetometry of magnetic fields > 0.1 T.
• The developed probes offer a versatile solution for magnetic field sensing across a broad temperature spectrum.
• The sensor design allows for high readout rates and excellent sensitivity, suitable for advanced applications.