13C NMR study of the magnetic properties of the quasi-one-dimensional conductor, (TMTTF)2SbF6

TL;DR

This study uses 13C NMR to explore how pressure affects the magnetic phases of (TMTTF)2SbF6, revealing pressure-induced phase transitions, charge-order suppression, and the emergence of a new antiferromagnetic phase.

Contribution

It provides detailed insights into pressure-dependent magnetic phase transitions and charge-order suppression in (TMTTF)2SbF6 using 13C NMR, identifying a new antiferromagnetic phase under pressure.

Findings

Confirmation of antiferromagnetic phase at ambient pressure.

Charge-ordering is suppressed under pressure and not observed above 8 kbar.

Identification of a new antiferromagnetic phase (AFII) at pressures above 20 kbar.

Abstract

Magnetic properties in the quasi-one-dimensional organic salt (TMTTF)2SbF6 are investigated by 13C NMR under pressures. Antiferromagnetic phase transition at ambient pressure (AFI) is confirmed. Charge-ordering is suppressed by pressure and is not observed under 8 kbar. For 5 < P < 20 kbar, a sharp spectrum and the rapid decrease of the spin-lattice relaxation rate 1/T1 were observed below about 4 K, attributed to a spin-gap transition. Above 20 kbar, extremely broadened spectrum and critical increase of 1/T1 were observed. This indicates that the system enters into another antiferromagnetic phase (AFII) under pressure. The slope of the antiferromagnetic phase transition temperature T_AFII, dT_AFII/dP, is positive, while T_AFI decreases with pressure. The magnetic moment is weakly incommensurate with the lattice at 30 kbar.