Growth and characterization of millimeter-sized single crystals of CaFeAsF

High-quality and sizable single crystals are crucial for studying the intrinsic properties of unconventional superconductors, which are lacking in the 1111 phase of Fe-based superconductors. Here we report the successful growth of CaFeAsF single crystals with sizes of 1–2 mm using the self-flux method. Owing 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 single-crystal x-ray diffraction data, which confirms earlier reports 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 antiferromagnetic transition, was also detected in the resistivity data. Our results supply a basis from which to propel physical investigations of the 1111 phase of Fe-based superconductors.