Crystal Structure and Physical Properties of a Layered Oxyarsenide Sr₂VCrAsO₃

We report the synthesis, crystal structure, and physical properties of the mixed transition-metal oxyarsenide Sr₂VCrAsO₃. The compound has an ordered intergrowth structure with the perovskite-like layers of "Sr₃V₂O₆" and the ThCr₂Si₂-type layers of "SrCr₂As₂" stacking alternately along the crystallographic <i>c</i> axis, in which ∼10% mixed occupancy between V and Cr is present for the sample synthesized by solid-state reactions. The electrical resistivity data show semiconducting-like behavior, probably associated with the occupancy disorders in the CrAs layers. The magnetic measurement reveals two anomalies at <i>T</i>₁ ≈ 85 and <i>T</i>₂ ≈ 335 K, which are attributed to short-range antiferromagnetic (AFM) ordering in the VO₂ planes and long-range AFM ordering in the CrAs layers, respectively. The neutron powder diffraction measurements indicate a C-type AFM ordering of Cr spins along the <i>c</i> axis within the CrAs layers. Compared with other CrAs-layer-based compounds, the <i>T</i>₂ value is remarkably reduced, probably due to the synergistic effect of the nearest-neighbor magnetic interaction, V doping in the CrAs layers, interlayer charge transfer, and enhanced two dimensionality.