Effect of external pressure on Tc of as-grown and thermally treated superconducting Rbx Fe2-ySe2 single crystals

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2013-03, Vol.7 (3), p.218-220
• Main Authors: Kanagaraj, M., Krzton-Maziopa, A., Kalai Selvan, G., Pomjakushina, E., Conder, K., Weyeneth, S., Puzniak, R., Arumugam, S.
• Format: Article
• Language: English
• Subjects: Annealing; Crystallography; high pressure effects; iron chalcogenides; magnetisation; Physics; Superconductivity
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.201206426

We report on the effect of external pressure on the superconducting transition temperature (Tc) of as‐grown and thermally treated single crystals of superconducting iron chalcogenide Rb0.85Fe1.9Se2. The superconducting transition temperature of 27.1 K at ambient pressure for the as‐grown sample was found to increase up to 33.2 K for the sample annealed for 3 h at 215 °C in vacuum. An increase of Tc up to 28.2 K was observed for the as‐grown sample at a pressure of 0.83 GPa. For all the studied crystals, annealed in the temperature range between 215 °C and 290 °C, the external pressure seems to decrease the superconducting transition temperature and a negative pressure coefficient of Tc was observed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) The external pressure effect on the superconducting transition temperature Tc of as‐grown and thermally treated single crystals of superconducting iron chalcogenide Rb0.85Fe1.9Se2 has been studied performing magnetisation measurements under pressure. The maximum Tc was found at 33.2 K for the crystal annealed for 3 h at 215 °C at zero pressure. Under external pressure, the as‐grown crystal shows a clear enhancement of Tc (maximum Tc ∼ 28.2 K at 0.83 GPa). However, a negative pressure effect on Tc observed in annealed samples (at 215 °C and 265 °C) subjected to external pressure indicates that some relaxation of excess Fe magnetic moments into the Fe2Se2 layers might have happened.