Upper critical fields and superconducting anisotropy of K0.70Fe1.55Se1.01S0.99 and K0.76Fe1.61Se0.96S1.04 single crystals
Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory Upton, NY 11973, USA
Accepted: 19 July 2011
We have investigated temperature and angular dependence of resistivity of K0.70(7)Fe1.55(7)Se1.01(2)S0.99(2) and K0.76(5)Fe1.61(5)Se0.96(4)S1.04(5) single crystals. The upper critical fields μ0Hc2(T) for both field directions decrease with the increase in S content. On the other hand, the angle-dependent magnetoresistivity for both compounds can be scaled onto one curve using the anisotropic Ginzburg-Landau theory. The obtained anisotropy of μ0Hc2(T) increases with S content, implying that S doping might decrease the dimensionality of certain Fermi surface parts, leading to stronger two-dimensional character.
PACS: 74.25.Op – Mixed states, critical fields, and surface sheaths / 74.70.Xa – Pnictides and chalcogenides / 74.25.F- – Transport properties
© EPLA, 2011