Sr₂Te₄V₂O₁₃Cl₂, a Layered Structure Forming a Canted Antiferromagnetic Ground State

Abstract

The 2D oxychloride, Sr 2 Te 4 V 2 O 13 Cl 2 , was synthesized by high-temperature solid-state synthesis in a closed silica ampule with low internal pressure of inert atmosphere. The crystal structure, determined by single-crystal diffraction, can be described with the orthorhombic space group, Pca2 1 (No. 29), with the pseudo-tetragonal unit cell, a = b = 8.802(1) Å and c = 19.221(2) Å. Cl, as well as Sr and Te, forms layers similar to that of Cu in SrCu 2 (BO 3 ) 2 ("SrCuBO"), one of the 11 Archimedean lattices. V(IV) shows the classical square pyramidal coordination, containing one short V−O distance, indicative of a vanadyl ion; furthermore, a relatively short V−V interatomic distance of 3.927(1) Å is found across a superexchange path V−O−V with an angle of 173.9(2)°. Initial magnetic investigations suggest that the compound is a canted antiferromagnet with a slightly negative Curie−Weiss constant of θ CW = −5.5 K and an effective magnetic moment of μ eff = 1.71 μ B V −1 . A significant second-order-like entropy release in the specific heat capacity measurement is observed in the same temperature range as a magnetic anomaly, as measured by magnetic susceptibility. This suggests a long-range ordering of magnetic spins below 3 K. Further magnetic data, in combination with the noncentrosymmetric atomic lattice, indicate that the ground state is a canted antiferromagnet.