Effect of nominal substitution of transition metals for excess Fe in Fe1+xSe superconductor

• Published in: Solid state communications Vol. 202; pp. 8 - 13
• Main Authors: Yadav, Anil K., Sanchela, Anup V., Thakur, Ajay D., Tomy, C.V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2015
• Subjects: Chemical pressure; Iron Chalcogenide; Substitution; Thermopower; Iron Chalcogenide; Substitution; Chemical pressure; Thermopower
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2014.10.027

Taking cue from the increase in the superconducting transition temperature (Tc) of Fe1+xSe via nominal (2wt%) substitution of Cr instead of excess Fe, we have now extended our study with nominal substitution (≤5wt%) with other transition metals (Ni, Co, Fe, Mn, Cr, V and Ti) in place of excess iron. The Tc is found to increase (maximum ~11K) or get suppressed depending on the substituted transition metal. Our studies indicate that the superconducting transition temperature depends on ionic size of the transition metal and amount of hexagonal phase present as impurity. •All polycrystalline samples FeTxSe (T: Ni, Co, Fe, Mn, Cr, V, T) are grown via single step solid state reaction method.•Structure of all samples have admixture of hexagonal and tetragonal.•The Tc is found to be enhanced by substitution of higher atomic radius atoms upto 30% compare to parent compound.•All compounds show an ‘S’ like interesting features in Seebeck measurement.•Could provide the alternate way to enhance the Tc of FeSe rather than excess Fe.