The role of Fe deficiency in FeySe0.5Te0.5 samples prepared by a melting process

• We investigate the role of the Iron deficiency in the FeySe0.5Te0.5 compound.
• The synthesized samples are prepared using a novel technique with a melting process.
• Samples with small iron deficiency show better superconducting properties.
• The highest Jc for the FeySe0.5Te0.5 compounds is reported in this work.

Fe content plays a primary role in the structural, magnetic and transport properties of Fe(Se,Te) compounds. In this work we investigate some of these properties in ipo-stoichiometric FeySe0.5Te0.5 samples (y ⩽ 1.00) prepared by a novel synthesis technique, involving a melting process. These samples are characterized by a pore-free microstructure with large and well interconnected grains. The composition Fe0.99Se0.5Te0.5 exhibits the best properties with an optimal critical temperature, sharp resistive and magnetic transitions, large hysteresis loops and high value of critical current density at zero field and 5 K.