Upper critical field, critical current density and activation energy of the new La1-xSmxOF0.5BiS2 (x = 0.2, 0.8) superconductor

TL;DR

This study investigates the superconducting properties of La1-xSmxOF0.5BiS2 with different Sm concentrations, focusing on critical fields, current density, and activation energy, revealing how Sm substitution affects these parameters.

Contribution

It provides the first detailed comparison of critical current density, upper critical field, and activation energy in La1-xSmxOF0.5BiS2 superconductors with varying Sm content.

Findings

Lower Hc2 values compared to Sm-free superconductor.

Higher critical current density with increased Sm content.

Strong flux pinning indicated by activation energy measurements.

Abstract

Critical current density (Jc), thermal activation energy (U0), and upper critical field (Hc2) of La1-xSmxO0.5F0.5BiS2 (x = 0.2, 0.8) superconductors are investigated from magnetic field dependent \r{ho}(T) studies. The estimated upper critical field (Hc2) has low values of 1.04 T for x = 0.2 and 1.41 T for x = 0.8. These values are lower than Sm free LaO0.5F0.5BiS2 superconductor (1.9 T). The critical current density (Jc) is estimated to be 1.35*105 A/cm2 and 5.07 *105 A/cm2 (2 K) for x = 0.2 and 0.8 respectively, using the Bean's model. The thermal activation energy (U0/kB) is 61 K for x = 0.2 and 140 K for x =0.8 as calculated from Arrhenius plots at low magnetic field (1 T) and indicates a strong flux pinning potential which might be co-existing with applied magnetic field.