Electrical and Magnetic Properties for Bulk FeSe and FeSe0.5Te0.5 Superconductors

• Published in: Journal of electronic materials 2021-03, Vol.50 (3), p.941-946
• Main Authors: Li, D., Zhang, B. L., Ming, H. W., Qin, X. Y., Zhang, J., Liu, H. J.
• Format: Article
• Language: English
• Subjects: Brief Communication; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crossovers; Density functional theory; Diamagnetism; Electronics and Microelectronics; Electrons; High temperature; Instrumentation; Lattice parameters; Low temperature resistance; Magnetic measurement; Magnetic properties; Magnetism; Materials Science; Optical and Electronic Materials; Solid State Physics; Superconductivity; Superconductors; Temperature; Transition temperature
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-020-08666-x

We report a one-step low temperature sintering method for preparing high quality FeSe and FeSe 0.5 Te 0.5 polycrystalline superconductors, and investigate their transport and magnetic properties. The low temperature resistance results show that onset temperatures of the superconducting transition for FeSe and FeSe 0.5 Te 0.5 are 11.06 K and 14.72 K, respectively. X-ray diffraction results demonstrate that Te alloying causes expansion of lattice parameters, and density functional theory calculations confirm that Te-5 p orbital electrons are related to the enhancement of the temperature of the superconducting transition. Magnetic measurements reveal that the superconducting diamagnetic transition appears at 9.35 K and 14.16 K for FeSe and FeSe 0.5 Te 0.5 , respectively, in keeping with the initial transition temperature of zero resistivity. In addition, high temperature transport results show that there is a sign crossover in the thermopower for FeSe and FeSe 0.5 Te 0.5 , which is due to the dominant contributions from electrons and holes.