Effect of Hydrostatic Pressure on Superconductivity in kappa-[(BEDT-TTF)1-X(Bedse-TTF)X]2Cu[N(CN)2]Br

TL;DR

This study investigates how static susceptibility and superconducting properties of a specific organic superconductor alloy change under pressure, revealing a non-monotonic relationship with initial growth followed by complex behavior.

Contribution

It provides new insights into pressure effects on superconductivity in BEDT-TTF based alloys, especially near the borderline of ambient pressure superconductivity.

Findings

Superconducting critical temperature shows non-monotonic pressure dependence.

Superconducting volume fraction initially increases with pressure below 0.3 kbar.

Pressure influences susceptibility and superconductivity in a complex manner.

Abstract

Static susceptibility of kappa-[(BEDT-TTF)1-x(BEDSe-TTF)x]2Cu[N(CN)2]Br alloys with the BEDSe-TTF content near the border-line of ambient pressure superconductivity (x~0.3) has been measured as a function of temperature, magnetic field, and pressure. A non-monotonic pressure dependence is observed for both the superconducting critical temperature and superconducting volume fraction, with both quantities showing growth under pressure in the initial pressure range P < 0.3 kbar. The results are discussed in comparison with the data on the related kappa-phase BEDT-TTF superconductors in which not a cation but anion sublattice is modified by alloying, namely the family kappa-(BEDT-TTF)2Cu[N(CN)2]Cl1-xBrx. PACS numbers: 74.62.Fj, 74.70.Kn.