  Here, we report self flux single crystal growth of FeTe1-xSex for x = 0 to
0.50 series via solid state reaction route,the resulted crystals as seen are
shiny. X Ray diffraction performed on the surface of crystals elucidated the
growth in 00l plane, i.e. orientation in c direction only. Scanning electron
microscopy (SEM) images showed slab like morphology and EDX (Energy dispersive
X ray analyzer) confirmed that the crystals are closed to their designed
compositions. Rietveld analysis of the XRD patterns of crushed crystal powders
showed that the cell parameters decrease with Se content increase. Coupled
magnetic and structural phase transition temperature, seen as a step in
resistivity for the lower Se concentration and it is not detected for higher x
values. Superconductivity is observed by resistivity measurement for higher Se
concentration with a maximum temperature of 14K at x = 0.50. Thermally
Activated Flux Flow (TAFF) analysis based on high field transport measurements
in superconducting region done for x = 0.20 crystal. Raman spectroscopy at room
temperature of synthesized samples exhibits all the allowed phonon modes with
slight shift to higher frequency with Se content. Mossbauer spectra of
FeTe1-xSex crystals series were recorded at 300 and 5K. At 5K, the average
hyperfine field decreases systematically with Se content increase from 10.6 to
6.1Tesla for x = 0.0 to x = 0.20 samples. This indicates a possibility of
co-existing magnetism and superconductivity in x = 0.07 to 0.20 crystals. For x
= 0.50 sample, no hyperfine field related to magnetic ordering is seen. Based
on above results, detailed phase diagram of the FeTe1-xSex compounds is defined
in the present study.
