Interplay between conducting and magnetic systems in the antiferromagnetic organic superconductor $\kappa$-(BETS)${}_2$FeBr${}_4$

Abstract

The mutual influence of the conduction electron system provided by organic donor layers and magnetic system localized in insulating layers of the molecular charge transfer salt $\kappa$-(BETS)${}_2$FeBr${}_4$ has been studied. It is demonstrated that besides the high-field re-entrant superconducting state, the interaction between the two systems plays important role for the low-field superconductivity. The coupling of normal-state charge carriers to the magnetic system is reflected in magnetic quantum oscillations and can be evaluated based on the angle-dependent beating behaviour of the oscillations. On the other hand, the conduction electrons have their impact on the magnetic system, which is revealed through the pressure-induced changes of the magnetic phase diagram of the material.

6 pages, 6 figures