Room-Temperature Pulsed Dynamic Nuclear Polarization at 7 T
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-05-20 |
| Journal | The Journal of Physical Chemistry Letters |
| Authors | Alexander A. Nevzorov, Sergey Milikisiyants, AntonĆn Marek, Ilia Kaminker, Alex I. Smirnov |
| Institutions | Tel Aviv University, North Carolina State University |
Abstract
Section titled āAbstractāPulsed dynamic nuclear polarization (DNP) can enhance NMR signals by more than 2 orders of magnitude and is applicable to spin systems with short-lived electronic polarization. Recently, several pulsed DNP sequences were demonstrated at low magnetic fields. However, pulsed DNP at magnetic fields of modern NMR spectrometers (7 T and above) necessitates addressing major technical challenges for generating sufficiently high mm-wave <i>B</i><sub>1e</sub> amplitudes to match the nuclear Larmor frequencies. Here we describe a first-of-its-kind ESR/NMR spectrometer for pulsed DNP and phase-sensitive electronic detection operating at 7 T magnetic field. Generation of <i>B</i><sub>1e</sub> fields with amplitudes of <i>ca</i>. 75 MHz was made possible by employing a pulsed extended interaction klystron and piezo-tunable photonic-band gap resonators with unloaded quality factors <i>Q</i> ā 1500. Room-temperature NOVEL DNP yielded natural-abundance <sup>13</sup>C NMR signal gains of up to 800 for a 30 Ī¼m thick crystal of a synthetic diamond. Simultaneous coherent manipulation of the electronic and nuclear spins was demonstrated by <sup>13</sup>C-detected electron Rabi nutations.