Abstract
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.