Growth and Characterization of Millimeter-sized Single Crystals of CaFeAsF

TL;DR

This study reports the successful growth of large, high-quality CaFeAsF single crystals and investigates their structural and transport properties, revealing key phase transitions relevant to Fe-based superconductor research.

Contribution

First demonstration of growing millimeter-sized CaFeAsF single crystals using the self-flux method and detailed characterization of their structural and transport properties.

Findings

Structural transition at 121 K confirmed by multiple measurements.

Detection of an antiferromagnetic transition at 110 K.

High-quality crystals enable reliable physical property investigations.

Abstract

High-quality and sizable single crystals are crucial for studying the intrinsic properties of unconventional superconductors, which are lacking in the 1111 phase of the Fe-based superconductors. Here we report the successful growth of CaFeAsF single crystals with the sizes of 1-2 mm using the self-flux method. Owning to the availability of the high-quality single crystals, the structure and transport properties were investigated with a high reliability. The structure was refined by using the single-crystal x-ray diffraction data, which confirms the reports earlier on the basis of powder data. A clear anomaly associated with the structural transition was observed at 121 K from the resistivity, magnetoresistance, and magnetic susceptibility measurements. Another kink-feature at 110 K, most likely an indication of the antiferromagnetic transition, was also detected in the resistivity data. Our results supply a basis to propel the physical investigations on the 1111 phase of the Fe-based superconductors.