Effect of Tellurium Substitution on the Properties of Iron Di-Selenide

FeSe2 and FeTe2 both crystallize in C-18 Marcasite type orthorhombic structure. We have attempted to substitute tellurium in FeSe2 by solid state reaction method and polycrystalline samples Fe(Se2-xTex) with x=0.2,0.6,1.0,1.4,1.8 were synthesis to study the effect of substituting Te with Se in FeSe2. Phillips X-ray diffractometer is recorded XRD patterned using CuKα radiation into 2θ range of 10 to 90. XRD revealed that both the samples posses orthorhombic The lattice parameter and the cell volume increases monotonically with increasing Te concentration structure Scanning electron microscopy (SEM) reveals irregularly shaped particle with an average size 254.5nm to 678.2nm. Fe Mossbauer spectroscopy experiments were performed at 300K using Co Rhodium source. Mossbauer spectra of Fe(Se2-xTex) with x=0.2,0.6,0.8,1.0,1.4 & 1.8 revealed paramagnetic character Isomer shift(IS)and qudropole shift (QS) vary considerably with absence of internal hyperfine fields compared to pure FeSe2. Electrical resistivity of Fe(Se2-xTex) with x=0.6 and 1.0 revealed that the samples shows semiconducting behavior in case of variation of resistance with magnetic field at different temperatures. KeywordsXray diffraction, Mossbauer effect, Scanning electron microscopy, Electrical resistivity.