Synthesis and properties of SmO0.5F0.5BiS2 and enhancement in Tc in La1-ySmyO0.5F0.5BiS2

TL;DR

This study reports the synthesis, crystal structure, and superconducting properties of SmO0.5F0.5BiS2 and La1-ySmyO0.5F0.5BiS2, demonstrating that Sm substitution enhances Tc up to 4.6 K, with structural and magnetic characterizations.

Contribution

It introduces a new oxy-bismuth-sulfide compound with improved superconducting transition temperature through Sm substitution, expanding understanding of structure-property relationships.

Findings

SmO0.5F0.5BiS2 is isostructural with LaOBiS2.

Maximum Tc of 4.6 K achieved at y=0.8.

Both compounds are paramagnetic and semiconducting down to 2 K.

Abstract

Crystal structure and properties of a new member of oxy-bismuth-sulfide SmO1-xFxBiS2 are reported here. The compounds SmO1-xFxBiS2 (x = 0.0 and 0.5) are found to be isostructural with LaOBiS2 and crystallize in the CeOBiS2 type structure (P4/nmm). Sm substitution in LaO0.5F0.5BiS2, (La1-ySmyO0.5F0.5BiS2), leads to a gradual decrease in a-lattice constant however the c-lattice constant does not show such a gradual trend. Enhancement in Tc is achieved upon partially substituting La by smaller Sm ion. Maximum Tc ~ 4.6 K was observed for composition with y = 0.8. Disobeying this trend Tc disappears unexpectedly in composition SmO0.5F0.5BiS2 (y = 1.0). Both the undoped and F-doped (x = 0.0 and 0.5) compounds are paramagnetic exhibiting semiconducting behavior down to 2 K.