Pressure enhanced superconductivity at 10 K in La doped EuBiS2F

TL;DR

This study demonstrates that applying pressure significantly enhances the superconducting transition temperature of La-doped EuBiS2F from 2.2 K to over 10 K, revealing pressure-induced phase transitions.

Contribution

It reports the discovery of pressure-induced enhancement of Tc and phase transformation in Eu0.5La0.5BiS2F, a new superconducting material with tunable properties.

Findings

Superconductivity in Eu0.5La0.5BiS2F is enhanced from 2.2 K to over 10 K under pressure.

Evidence of two phases with different Tc values at intermediate pressures.

Pressure induces a phase transition from low Tc to high Tc state.

Abstract

Polycrystalline Eu0.5La0.5BiS2F was synthesized by solid state reaction which crystallizes in the tetragonal CeOBiS2 structure (P4/nmm). We report here enhancement of Tc to 2.2 K in Eu0.5La0.5BiS2F (by electron doping in EuBiS2F with Tc ~ 0.3 K). Eu0.5La0.5BiS2F is semiconducting down to 3 K and an onset of superconductivity is seen at 2.2 K at ambient pressure. Upon application of pressure the Tc could be enhanced upto 10 K. Step like features are seen in the resistivity curves at intermediate pressures (0.5 - 1 GPa) which hints towards the possible existence of two phases with different Tc. At a pressure above 1.38GPa, the Tconset remains invariant at 10 K but the Tc(\r{ho}=0) is increased to above 8.2 K. There is a possible transformation from a low Tc phase to a high Tc phase by application of pressure.