Growth of millimeter-sized high-quality CuFeSe$_2$ single crystals by the molten salt method and study of their semiconducting behavior

TL;DR

This study reports the successful growth of millimeter-sized high-quality CuFeSe$_2$ single crystals using a molten salt method and investigates their semiconducting and magnetic properties.

Contribution

It introduces a novel molten salt growth technique for CuFeSe$_2$ crystals and characterizes their composition, magnetic transition, and semiconducting behavior.

Findings

Crystals are nearly 1.6x1.2x1.0 mm3 in size.

Crystals have stoichiometric composition CuFeSe$_2$.

Magnetic transition occurs below 146 K with semiconducting behavior.

Abstract

An eutectic AlCl$_3$/KCl molten salt method in a horizontal configuration was employed to grow millimeter-sized and composition homogeneous CuFeSe$_2$ single crystals due to the continuous growth process in a temperature gradient induced solution convection. The typical as-grown CuFeSe$_2$ single crystals in cubic forms are nearly 1.6$\times$1.2$\times$1.0 mm3 in size. The chemical composition and homogeneity of the crystals was examined by both inductively coupled plasma atomic emission spectroscopy and energy dispersive spectrometer with Cu:Fe:Se = 0.96:1.00:1.99 consistent with the stoichiometric composition of CuFeSe$_2$. The magnetic measurements suggest a ferrimagnetic or weak ferromagnetic transition below T$_C$ = 146 K and the resistivity reveals a semiconducting behavior and an abrupt increase below T$_C$.