Study on the Structural and Superconducting Properties of Ag-Dilute-Doped Fe(Se,Te) Superconductors

Doping transition metal elements, including Ag, to replace Fe atoms is an effective means to control the superconducting properties of iron-based superconducting materials. In this study, crystalline samples of Fe(Se_0.4Te_0.6) with Ag content below 1% relative to Fe were prepared using a self-flux method, and two choices of dopant, elemental Ag and Ag₂O, were tested. Structural characterization and morphology analysis revealed that in samples directly doped with elemental Ag, Ag may not replace the original atoms in Fe(Se,Te) but is more likely to enter the interlayer gaps. Critical current density (J_c) extracted from magnetic measurements showed an enhancement in the superconducting properties, particularly the critical current density, of these samples. Conversely, doping with Ag₂O possibly led to the incorporation of dopants into the original lattice, resulting in a decrease in superconducting performance. The research comparing the behavior differences of different dopants provides an important reference for subsequent studies in this field.