Transport properties and anisotropy of Rb0.8Fe2Se2 single crystals
Abstract
Single crystals of Rb0.8Fe2Se2 are successfully synthesized with the superconducting transition temperatures Tconset= 31 K and Tczero= 28 K. A clear anomaly of resistivity was observed in the normal state at about 150 K, as found in a similar system KxFe2Se2. The upper critical field has been determined with the magnetic field along ab-plane and c-axis, yielding an anisotropy of about 3.5. The angle dependent resistivity measured below Tc allow a perfect scaling feature based on the anisotropic Ginzburg-Landau theory, leading to a consistent value of the anisotropy which decreases from about 3.6 at around Tc to 2.9 at 27 K. Comparing to the anisotropy determined for Ba0.6K0.4Fe2As2 and Ba(Fe0.92Co0.08)2As2 using the same method, we find that the present sample is more anisotropic and the Fermi surfaces with stronger two dimensional characters are expected.