The upper critical field in the BiCh2-based superconductors CeOBiS1.7Se0.3 and PrO0.5F0.5BiS2-xSex (x = 0, 0.3)

TL;DR

This study investigates the upper critical magnetic field in specific BiCh2-based superconductors, revealing how magnetic ordering and spin-orbit coupling influence superconductivity and critical field limits.

Contribution

It provides new insights into the effects of ferromagnetic ordering and antisymmetric spin-orbit coupling on the upper critical field in BiCh2-based superconductors.

Findings

CeOBiS1.7Se0.3 has a smaller in-plane Bc2 than the orbital and Pauli limits.

PrO0.5F0.5BiS2-xSex exhibits high in-plane Bc2 values.

Antisymmetric spin-orbit coupling enhances Bc2 in non-centrosymmetric structures.

Abstract

We report the upper critical field (Bc2) in the BiCh2-based superconductors CeOBiS1.7Se0.3 and PrO0.5F0.5BiS2-xSex (x = 0, 0.3). Single crystals of CeOBiS1.7Se0.3 and PrO0.5F0.5BiS2-xSex (x = 0, 0.3) were grown using the flux method. Single-crystal structural analysis revealed that the crystal structure at room temperature is tetragonal (P4/nmm). Through electrical resistivity and magnetization measurements, bulk superconductivity was observed in all samples. For CeOBiS1.7Se0.3, the in-plane Bc2 is smaller than the conventional orbital limit and Pauli limit, suggesting that ferromagnetic ordering, which has been observed in a related Ce-containing BiCh2-based compound, affects Bc2 and superconductivity. In contrast, high in-plane Bc2 was observed for PrO0.5F0.5BiS2-xSex (x = 0, 0.3). We propose that the in-plane Bc2 is enhanced by antisymmetric spin-orbit coupling, which arises from the lack of local inversion symmetry.