- Duminda Sanjeewa, Clemson University, Clemson
The crystal chemistry of vanadium is of great interest because of the presence of different oxidation states and coordination geometries of vanadium that lead to great structural variety and versatility. This presentation will focus on the synthesis and magnetic properties of one- and two-dimensional vanadate systems. The one dimensional systems include Ba2V(VO4)2(OH)-brackebuschite and SrMn(VO4)(OH)-descloizite-type compounds. Magnetic characterization of Ba2V(VO4)2(OH) reveals a broad feature over a wide temperature range with a maximum at ~100 K, indicating an energy gap could exist between the antiferromagnetic singlet ground state and excited triplet states, making it potentially of interest for quantum magnetic studies. Further, the growth of large single crystals of SrMn(VO4)(OH) allowed us to perform neutron diffraction measurements, indicating that this compound orders below 30 K in a canted antiferromagnetic state with small ferromagnetic component along the chain axis. This presentation will also highlight the synthesis and characterization of a large number of 2D magnetic materials including Na2BaFe(VO4)2, K2Mn3(VO4)2(CO3), K2Mn3(VO4)2(OH)2, Mn5(VO4)2(OH)4, and Mn6(VO4)3(OH)2. These materials possess a variety of triangular, honeycomb, and kagome-type transition metal lattices as the source of complex magnetic behavior. The rich vanadate crystal chemistry, versatility of the synthetic technique, and variety of the magnetic interactions observed bodes well for continued study.