Vortex dynamics in phase separated Tl0.58Rb0.42Fe1.72Se2 crystals. (December 2016)

• Record Type: Journal Article
• Authors: Haberkorn, N.; Troiani, H.; Condó, A.M.; Wang, Hangdong; Mao, Qianhui; Fang, Minghu
• Is Part Of: Solid state communications. Volume 247(2016)
• Page Start: 88
• Page End: 93
• Publication Date: 2016-12
• Subjects: A. Superconductors -- C. Structure and characterization -- D. Phenomena and properties; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2016.08.022
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: We report the critical current density J c and the vortex dynamics in phase-separated Tl0.58 Rb0.42 Fe1.72 Se2 crystals by performing magnetization measurements. Structural investigation reveals micro- and nanoscopic phase separation between 122 (superconducting) and 245 (not superconducting) phases. Micrometric phase separation refers to 245 islands with typical diameters of 2 µm embedded in a multiply-connected 122 superconducting network. Nanoscopic phase separation refers to 245 nanoprecipitates embedded in the 122 superconducting paths. The 245 nanoprecipitates with size comparable to the coherence length produce strong vortex pinning. It was observed that the temperature dependence of the flux creep rate presents a peak at intermediate temperatures and magnetic fields lower than 0.5 T. The peak is systematically suppressed as the magnetic field is increased, and it could be related with relaxation generated by double-kink excitations. Double-kinks are low-energy depinning excitations usually associated with strong pinning produced by correlated disorder. Highlights: Transmission electron microscopy analysis reveals phase coexistence. Vortex dynamics for Tl0.58 Rb0.42 Fe1.72 Se2 single crystals is reported. Flux creep rates present a peak at intermediate temperatures for fields smaller than 0.5 T.