Evolution of vortex matter, phase diagram, and upper critical field in the FeSe <sub> 1− <i>x</i> </sub> S <sub> <i>x</i> </sub> system
В. А. Власенко, A. V. Sadakov, Tatiana Romanova, S. Yu. Gavrilkin, A.V. Dik, O. A. Sobolevskiy, Б. И. Массалимов, Д. А. Чареев, A. N. Vasiliev, Е.И. Мальцев, T. E. Kuzmicheva
Abstract
Abstract We present a comprehensive study of vortex matter in the FeSe 1− x S x system with various doping degree. The influence of sulphur substitution on peak effect occurrence is studied. Additionally, we study a possible vortex liquid–vortex glass/lattice transition and find an evidence that the vortex liquid–vortex glass phase transition in FeSe 1− x S x has a quasi two–dimensional nature. We investigate the upper critical field behaviour in FeSe 1− x S x system, and found that the upper critical field is higher than that predicted by the Werthamer–Helfand–Hohenberg (WHH) model, whereas its temperature dependence could be fitted within a two-band framework. Finally, a detailed H – T phase diagram is presented.