Study of the structural, superconducting and electrochemical corrosion properties of F and Se co-doped LaOBiS2 materials

This study was conducted to successfully synthesize LaOBiS2, F-doped LaOBiS2, Se-doped LaOBiS2, and F and Se-codoped LaOBiS2 by the standard solid state reaction route, and study the structural, superconductivity, and electrochemical corrosion properties. The layered nature of the pure and doped LaOBiS2 samples' crystals and their growth along the c-axis were revealed by structural investigations. Results revealed that Fe and Se doping caused expansion along the c-axis, respectively, confirming the effectiveness of the doping method. Studies on the relationship between resistance and temperature revealed a rapid superconducting transition for the F-doped LaOBiS2 system with a Tc of 3.18 K, and F-ion substitution can increase the superconductivity. The results demonstrated that Se substitution could be the cause of the elevated carrier mobility by successfully suppressing local distortion. Results showed that F and Se doping increased the density of electron carriers. The temperature dependence of the ZFC and FC DC magnetic susceptibilities was studied, and the results revealed that the higher Tc of the F and Se-codoped LaOBiS2 led to a diamagnetic transition into the superconducting state at Tc similar to 3.8 K. According to electrochemical corrosion investigations, F and Se codoped LaOBiS2 had a higher charge transfer resistance than other electrodes, showing a synergistic effect of F and Se on enhancing corrosion resistance.