Crystal structure and physical properties in Fe-Te-Br

Within a spin fluctuation driven scenario of superconductivity the results indicate that FeTe with doping is a likely higher-temperature superconductor. However, Fe$_{1+x}$Te forms the same tetragonal structure with 0.06 \textless y \textless 0.17. The excess Fe (2) not only stabilizes the PbO-type crystal structure with space group P4/nmm but also is strongly magnetic as an electron donor while the deficit of Fe in Fe$_{1-x}$Te will result in the hexagonal structure with space group P6$_{\mathrm{3}}$/mmc. In this work, five single tetragonal phase samples with space group P4/nmm and three single hexagonal phase samples with space group P6$_{\mathrm{3}}$/mmc have been made in Fe-Te-Br. Magnetic and electrical properties as well as the possibility of high-T$_{c}$ superconductivity in the Fe-Te-Br system investigated will be discussed.