ESR spectrometer with a loop-gap resonator for cw and time resolved studies in a superconducting magnet

TL;DR

This paper presents a versatile ESR spectrometer with a loop-gap resonator capable of cw and time-resolved studies in high magnetic fields and wide temperature ranges, suitable for investigating strongly interacting spin systems.

Contribution

The design of a compact, high-frequency ESR spectrometer with a loop-gap resonator embedded in a variable temperature magnet system is introduced, enabling advanced studies in high-field and low-temperature conditions.

Findings

Successful measurement of MgB₂ superconductor

Effective time-resolved ESR experiments demonstrated

Operates across a broad temperature and magnetic field range

Abstract

The design and performance of an electron spin resonance spectrometer operating at 3 and 9 GHz microwave frequencies combined with a 9 T superconducting magnet is described. The probehead contains a compact two-loop, one gap resonator and is embedded in the variable temperature insert of the magnet enabling measurements in the 0- 9 T magnetic field and 1.5-400 K\ temperature range. The spectrometer allows studies on systems where resonance occurs at fields far above the $g$ $\approx 2$ paramagnetic condition such as in strongly interacting spin systems. The low quality factor of the resonator allows time resolved experiments such as e.g. longitudinally detected ESR. We demonstrate the performance of the spectrometer on the MgB$_{2}$ superconductor and the RbC$_{60}$ conducting alkaline fulleride polymer.