Structural transition and anisotropic properties of single crystalline SrFe2As2

TL;DR

This study reports the growth of large SrFe2As2 single crystals, characterizes their structural phase transition at 198 K, and examines their anisotropic physical properties without observing superconductivity down to 1.8 K.

Contribution

It provides detailed analysis of the structural transition and anisotropic properties of SrFe2As2 single crystals, including phase coexistence and physical anomalies.

Findings

Structural phase transition at 198 K from tetragonal to orthorhombic.

Anomalies in resistivity, Hall resistivity, specific heat, and magnetic susceptibility.

Coexistence of phases between 198 K and 160 K.

Abstract

Plate-like single crystals of SrFe2As2 as large as 3x3x0.5 mm3 have been grown out of Sn flux. The SrFe2As2 single crystals show a structural phase transition from a high temperature tetragonal phase to a low temperature orthorhombic phase at To = 198 K, and do not show any sign of superconductivity down to 1.8 K. The structural transition is accompanied by an anomaly in the electrical resistivity, Hall resistivity, specific heat, and the anisotropic magnetic susceptibility. In an intermediate temperature range from 198 K to 160 K, single crystal X-ray diffraction suggests a coexistence of the high-temperature tetragonal and the low-temperature orthorhombic phases.