NMR measurements in dynamically controlled field pulse

TL;DR

This paper introduces a versatile NMR spectrometer with SDR technology that enables precise measurements in high pulsed magnetic fields by dynamically controlling the field, allowing for novel experiments like measuring nuclear spin-lattice relaxation rates.

Contribution

The paper presents a new NMR spectrometer architecture with dynamic field control, enabling high-precision measurements in pulsed magnetic fields previously inaccessible.

Findings

Confirmed reproducibility of field pulses using NMR spectroscopy.

Successfully measured nuclear spin-lattice relaxation rate in pulsed fields.

Implemented NMR spectrum measurement modes adaptable to sample properties.

Abstract

We present the architecture of the versatile NMR spectrometer with software-defined radio (SDR) technology and its application to the dynamically controlled pulsed magnetic fields. The pulse-field technology is the only solution to access magnetic fields greater than 50 T, but the NMR experiment in the pulsed magnetic field was difficult because of the continuously changing field strength. The dynamically controlled field pulse allows us to perform NMR experiment in a quasi-steady field condition by creating a constant magnetic field for a short time around the peak of the field pulse. We confirmed the reproducibility of the field pulses using the NMR spectroscopy as a high precision magnetometer. With the highly reproducible field strength we succeeded in measuring the nuclear spin-lattice relaxation rate $1/T_1$, which had never been measured by the pulse-field NMR experiment without dynamic field control. We also implement the NMR spectrum measurement with both the frequency-sweep and field-sweep modes and discuss the appropriate choice of these modes depending on the magnetic properties of sample to be measured. This development, with further improvement at a long-duration field pulse, will innovate the microscopic measurement in extremely high magnetic fields.