Strongly canted antiferromagnetic ground state in Cu3(OH)2F4

An unique crystal structure of copper hydroxyl-fluorite, Cu3(OH)2F4, hosts the trimerized chains of both edge-sharing and corner-sharing CuO2F2 plaquettes. The results of the comprehensive study of this compound, including new synthetic route, measurements of specific heat, ac- and dc-susceptibility, pulsed field magnetization, electron spin resonance, muon spin rotation and relaxation and first principles calculations are presented. The data evidence magnetic phase transition at TC = 12.5 K into canted antiferromagnetic state which is due to antisymmetric Dzyaloshinskii-Moriya (DM) exchange interaction. No alteration of DM component stemming from the intrinsic features of the crystal lattice in Cu3(OH)2F4 results in unusually large spontaneous magnetization. At T < TC, the remanence MR constitutes significant portion of saturation magnetization MS which defines the canting angle φ = 4°. © 2018 Elsevier B.V