Aging Effects on Superconducting Properties of BiS2-Based Compounds: First-12-Year Restudy

TL;DR

This study examines how aging over 12 years affects the superconducting properties of BiS2-based compounds, revealing slight degradation in some samples and strain reduction in others, providing insights into their long-term stability.

Contribution

It provides the first long-term (12-year) investigation of aging effects on BiS2-based superconductors synthesized in 2012, highlighting changes in their superconducting properties over time.

Findings

Bi4O4S3 retains bulk superconductivity after 12 years with minor Tc reduction

LaO0.5F0.5BiS2 shows decreased Tc, indicating strain reduction due to aging

Aging impacts superconducting transition temperatures and strain in BiS2-based compounds

Abstract

Decomposition of superconductors sometimes becomes crucial when studying essential physical properties of the superconductors. For example, the cuprate superconductor YBa2Cu3O7-d decomposes by long-time air exposure. In this study, we investigate the aging effects on superconducting properties of BiS2-based superconductors Bi4O4S3 and LaO0.5F0.5BiS2, both were first synthesized in 2012, using their polycrystalline samples synthesized several years ago. We find that 12-year-old Bi4O4S3 samples exhibit bulk superconductivity with a slight degradation of the superconducting transition temperature (Tc) of 0.2 K. For a high-pressure-synthesized LaO0.5F0.5BiS2 sample, clear decrease in Tc is observed, which suggests that high-pressure strain is reduced by aging.