Note: Commercial SQUID magnetometer-compatible NMR probe and its application for studying a quantum magnet

Area of Science:

• Condensed Matter Physics
• Quantum Magnetism
• Materials Science

Background:

• Nuclear Magnetic Resonance (NMR) is a powerful technique for probing magnetic properties.
• Studying quantum magnetic materials requires sensitive and versatile measurement tools.
• Existing NMR probes may have limitations in compatibility with specialized equipment like SQUID magnetometers.

Purpose of the Study:

• To develop a compact NMR probe compatible with superconducting quantum interference device (SQUID) magnetometers.
• To demonstrate the probe's utility in low-temperature measurements of magnetic systems.
• To investigate the spin dynamics of a model quantum magnet, MoOPO4.

Main Methods:

• Construction of a compact NMR probe utilizing trimmer chip capacitors for the tank circuit.
• Integration of the NMR probe with a commercial SQUID magnetometer.
• Low-temperature (T-dependence) NMR measurements on a magnetic insulator (MoOPO4).

Main Results:

• The developed NMR probe is compatible with SQUID magnetometers.
• The NMR tank circuit exhibits weak temperature dependence, enabling ligand-ion NMR studies.
• 31P NMR results align with bulk susceptibility and neutron scattering data.
• Unconventional spin dynamics were observed in MoOPO4.

Conclusions:

• The compact NMR probe is a viable tool for low-temperature studies of quantum magnets.
• The probe facilitates detailed investigation of magnetic systems, complementing other experimental techniques.
• The study provides new insights into the spin dynamics of MoOPO4, a model S=1/2 quantum magnet.