Bulk Crystal Growth and Single-Crystal-to-Single-Crystal Phase Transitions in the Averievite CsClCu5V2O10

Quasi-two-dimensional averievites with triangle-Kagome-triangle trilayers are of interest due to their rich structural and magnetic transitions and strong spin frustration that are expected to host a quantum spin liquid ground state with suitable substitution or doping. Herein, we report the growth of bulk single crystals of averievite CsClCu5V2O10 with dimensions of several millimeters on the edge in order to (1) address the open question of whether the room-temperature crystal structure is P3 m1, P3, or P21/c or else, (2) to elucidate the nature of phase transitions, and (3) to study direction-dependent physical properties. Single-crystal-to-single-crystal structural transitions at similar to 305 and similar to 127 K were observed in the averievite CsClCu5V2O10 single crystals. The nature of the transition at similar to 305 K, which was reported as a P3 m1-P21/c transition, was found to be a structural transition from high-temperature P3 m1 to low-temperature P3 by combining variable-temperature synchrotron X-ray single crystal and high-resolution powder diffraction. In-plane and out-of-plane magnetic susceptibility and heat capacity measurements confirm a first-order transition at 305 K, a structural transition at 127 K, and an antiferromagnetic transition at 24 K. These averievites are thus ideal model systems for a deeper understanding of structural transitions and magnetism.