YCrWO6: Polar and Magnetic Oxide with CaTa2O6-Related Structure

A new polar and magnetic oxide, YCrWO6, was successfully synthesized and characterized. YCrWO6 crystallizes in polar orthorhombic space group Pna2(1) (no. 33) of edge-sharing dimers of CrO6 and WO6 octahedra, which are connected by corner-sharing to form a three-dimensional framework structure with Y3+ cations located in the channels. The structure of YCrWO6 is related to that of CaTa2O6; however, the ordering of Cr3+ and W6+ in the octahedral sites breaks the inversion symmetry of the parent CaTa2O6 structure. X-ray absorption near edge spectroscopy of YCrWO6 confirmed the oxidation state of Cr3+ and W6+. Temperature-dependent optical second harmonic generation measurements on YCrWO6 confirmed the noncentrosymmetric character and evidenced a noncentrosymmetric-to-centrosymmetric phase transition above 800 degrees C. Piezoresponse force microscopy measurements on YCrWO6 at room temperature show strong piezoelectric domains. Magnetic measurements of YCrWO6 indicate antiferromagnetic order at TN of similar to 22 K with Weiss temperature of -34.66 K.