Cascade of Phase Transitions and Large Magnetic Anisotropy in a Triangle-Kagome-Triangle Trilayer Antiferromagnet

Spins in strongly frustrated systems are of intense interest due to the emergence of intriguing quantum states including superconductivity and quantum spin liquid. Herein, we report the discovery of a cascade of phase transitions and large magnetic anisotropy in the averievite CsClCu 5 P 2 O 10 single crystals. Under a zero field, CsClCu 5 P 2 O 10 undergoes a first-order structural transition at around 224 K from high-temperature centrosymmetric P 3̅ m 1 to low-temperature noncentrosymmetric P 321 followed by an AFM transition at 13.6 K, and another AFM transition at ∼2.18 K. Based upon magnetic susceptibility and magnetization data with magnetic fields perpendicular to the ab plane, a phase diagram, consisting of a paramagnetic state, two AFM states, and two field-induced states including two magnetization plateaus, has been constructed. Our findings demonstrate that the quasi-2D CsClCu 5 P 2 O 10 exhibits rich structural and metamagnetic transitions, and the averievite family is a fertile platform for exploring novel quantum states.