New intercalation superconductor Lix(C6H16N2)yFe2-zSe2 with a very large interlayer-spacing and Tc = 38 K

TL;DR

This paper reports the synthesis of a new iron-based superconductor with a record interlayer spacing of 16.225 Å and a transition temperature of 38 K, achieved through lithium and hexamethylenediamine intercalation into FeSe.

Contribution

The study introduces a novel intercalation method creating the superconductor Lix(C6H16N2)yFe2-zSe2 with the largest interlayer spacing among FeSe-based compounds.

Findings

Superconducting transition confirmed by magnetic and electrical measurements.

Interlayer spacing of 16.225 Å is the largest among FeSe-based intercalation superconductors.

Transition temperature Tc is 38 K.

Abstract

A new iron-based superconductor, Lix(C6H16N2)yFe2-zSe2, with Tc = 38 K has successfully been synthesized via the intercalation of lithium and hexamethylenediamine into FeSe. The superconducting transition has been confirmed not only by magnetic susceptibility measurements but also by electrical resistivity ones. The interlayer spacing, namely, the dicstance between neighboring Fe layers, d, is 16.225(5) $\mathring{\text{A}}$, which is the largest among those of FeSe-based intercalation compounds. It has been found that the dependence of Tc on d in FeSe-based intercalation superconductors appears domic.