Two spin-canted antiferromagnetic orderings and a field-induced metamagnetic transition in SrMn

A new vanadate SrMn2(VO4)2(H2O)2 was synthesized and characterized by single-crystal X-ray analysis. It crystallizes in the monoclinic system with space group C2/m, and exhibits a quasi-one-dimensional (1D) structure. The Mn2+ ions form infinite linear-chains along the b-axis through edge-sharing oxygen atoms and further the linear-chains are connected by VO4 polyhedra into a layer in the ab-plane with Sr2+ ions residing in the space between the layers. Magnetic measurement results show that SrMn2(VO4)2(H2O)2 possesses two spin-canted antiferromagnetic orderings at ∼45 K and ∼7 K. The first ordering at ∼45 K possibly corresponds to a small deviation of spins from a strictly antiparallel arrangement. As the temperature decreases, further spin rotations occur leading to a steadier noncollinear antiferromagnetic phase, leading to the second ordering at ∼7 K. Also, a field-induced transition is observed at a critical field (0.4 T) below ∼7 K.