Chemical pressure effect on Tc in BiS2-based Ce1-xNdxO0.5F0.5BiS2

We have investigated the crystal structure and superconducting properties of the BiS2-based layered superconductor Ce1-xNdxO0.5F0.5BiS2. Bulk superconductivity was observed for x > 0.3, and the transition temperature was enhanced with increasing Nd concentration. The highest transition temperature was 4.8 K for x = 1.0. With increasing Nd concentration, the length of the a axis decreased, while the length of the c axis did not show a remarkable change. The chemical pressure along the a axis upon Nd substitution seemed to be linked with the inducement of bulk superconductivity. We found that the chemical pressure effect did not completely correspond to the external pressure effect.