Synthesis, characterization and multiferroic properties of the doubly-ordered polar perovskite NaLnNiWO6 (Ln = Er, Tm, and Lu)

The doubly-ordered perovskite NaLnNiWO6 (Ln = Lanthanide) have been prepared at high-pressure and high-temperature conditions. Analysis of powder X-ray diffraction data reveals that these compounds crystallize in a polar monoclinic (P21) structure. In addition to the commonly observed rock salt ordering of B-site cations, an unusual layered order of A-site cations occurs in these compounds. Highly charged second-order Jahn–Teller (SOJT) active cation (W6+) at the B-site stabilizes the layered ordering and the overall crystal structure. Magnetization and heat capacity measurements confirm the antiferromagnetic order of these compounds in the temperature (TN) range 18–21 K. Dielectric anomaly, and dc-bias signal at the magnetic ordering temperature (TN) reveal the multiferroic properties of these compounds. [Display omitted] •The doubly-ordered perovskite NaLnNiWO6 (Ln = Er, Tm, Lu) crystallize in polar P21.•These compounds NaLnNiWO6 are antiferromagnets (TN∼ 18 to 21 K).•These compounds exhibit change in polarization (ΔP) below TN.