High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3

TL;DR

This study uses high-frequency ESR to explore magnetic properties of beta'-(ET)2SF5CF2SO3, revealing a transition from a non-conventional state to a 3D antiferromagnetic phase at low temperatures.

Contribution

It provides new high-field ESR data that confirms a transition to a 3D antiferromagnetic phase, challenging previous assumptions of a spin-Peierls transition.

Findings

ESR results agree with NMR findings.

Evidence of a transition at 20 K not of spin-Peierls type.

Identification of a 3D antiferromagnetic phase at low temperatures.

Abstract

A systematic electron spin resonance (ESR) investigation of the low temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency range of ~200-700 GHz, using backward wave oscillator sources, and at fields up to 25 T. Newly acquired access to the high frequency and fields shows experimental ESR results in agreement with the nuclear magnetic resonance (NMR) investigation, revealing evidence that the transition seen at 20 K is not of conventional spin-Peierls order. A significant change of the spin resonance spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition into a three-dimensional-antiferromagnetic (3D AFM) phase.