Effect of nominal substitution of transition metals for excess Fe in Fe_{1+x}Se superconductor

TL;DR

This study investigates how substituting various transition metals for excess iron in Fe_{1+x}Se affects its superconducting transition temperature, revealing dependencies on ionic size, magnetic moment, and impurity phases.

Contribution

It extends previous research by systematically examining multiple transition metal substitutions and their effects on Tc in Fe_{1+x}Se superconductors.

Findings

Tc can increase by up to ~11 K or be suppressed depending on the metal used.

Superconducting properties depend on ionic size, magnetic moment, and impurity phases.

Different transition metals have distinct impacts on the superconducting transition temperature.

Abstract

Taking cue from the increase in the superconducting transition temperature (Tc) of Fe1+xSe via nominal (2 wt%) substitution of Cr instead of excess Fe, we have now extended our study with nominal substitution (<=5 wt%) with other transition metals (Ni, Co, Fe, Mn, Cr, V and Ti) in place of excess iron. The Tc is found to increase (maximum ~11 K) or get suppressed depending on the substituted transition metal. Our studies indicate that the superconducting transition temperature depends on various parameters like the ionic size of the transition metal, its magnetic moment as well as the amount of hexagonal phase present as impurity.