From zero-dimensional square tetramers to one-dimensional screw chains: a structural evolution in V 3+ -based lead vanadium fluorides

Abstract

Low-dimensional magnetic materials have attracted considerable attention because of the exotic phenomena arising from enhanced quantum fluctuations. Herein, two V3+-based lead vanadium fluorides, Pb6V4F24 and Pb7V4F26, were synthesized by hydrothermal reactions. Single-crystal X-ray diffraction shows that triclinic Pb6V4F24 contains isolated V4 tetramers, whereas monoclinic Pb7V4F26 features screw chains, representing a structural evolution from zero-dimensional clusters to one-dimensional chains. Long-range magnetic order is absent on both compounds down to 2 K. DFT calculations show that Pb6V4F24 behaves magnetically as weakly coupled antiferromagnetic dimers, whereas Pb7V4F26 contains ferromagnetic chains coupled by weak antiferromagnetic interactions.