Two energy scales of spin dimers in clinoclase Cu3(AsO4)(OH)3

摘要

Magnetic susceptibility and microscopic magnetic model of the mineralclinoclase Cu3(AsO4)(OH)3 are reported. This material can be well described asa combination of two nonequivalent spin dimers with the sizable magneticcouplings of J about 700 K and J(D2) about 300 K. Based on density functionaltheory calculations, we pinpoint the location of dimers in the crystalstructure. Surprisingly, the largest coupling operates between the structuralCu2O6 dimers. We investigate magnetostructural correlations in Cu2O6 structuraldimers, by considering the influence of the hydrogen position on the magneticcoupling. Additionally, we establish the hydrogen positions that were not knownso far and analyze the pattern of hydrogen bonding.