Study of a part of 3D phase diagram of Fe₁₋ₓTe₁₋ᵧSeᵧ (x=0.1, 0.14; y=0.03, 0.06, 0.15)
Dipl. Phys. Mamuka Chikovani (SONDERTERMIN im Inst. für Physik)

Recent discovery of superconductive iron chalcogenides raised a growing interest in the community of solid state physics. This finding opened a way to explore the new features of compounds bearing remarkable properties. The motivation was driven by recent studies in this system that reveal the structural phase transition, which believed to be governed by anti-ferromagnetic order competing with superconducting state. Hence, Its been decided to investigate a part of phase diagram where the coexistence of mixed phases takes place. The talk will be devoted to the synthesis and characterization of series of iron tellurium samples partially substituted by selenium. The Bridgman method has been used to grow single crystals. The obtained samples have been studied by means of various techniques such as powder x-ray and neutron diffraction, single crystal neutron scattering and AC magnetization measurements. According to the data collected during the experiments, an anti-ferromagnetic order has been emerged followed by a lattice distortion and further increase of a selenium concentration led to an occurrence of superconductivity.