Effect of Substitution and Heat Treatment Route on Polycrystalline FeSe_(0.5)Te_(0.5) Superconductors

摘要

The effect of atomic substitution of Te in iron based superconductors FeSe (1:1 type), which exhibits the simplest crystal structure among the iron-based superconductors, has been investigated in terms of structural, electronic transport, and magnetic properties. Polycrystalline samples with nominal Se:Te in FeSe_(1-x)Te_x samples for x = 0.5_(350℃), 0.5_(700℃), 0.6_(700℃), and 0.75_(700℃) were synthesized by the solid-state reaction method. In overall samples, it has been observed that the most superconducting properties seen in x = 0.6_(700℃) samples, for 0.5_(350℃) and 0.5_(700℃) samples latter showed better superconducting properties as dc magnetic susceptibility, ac susceptibility, and resistivity measurements and sample homogeneity. T_c enhancement is well correlated with the Te substitution up to 75%.