Polycrystalline magneto-optical transparent Pr₂Zr₂O₇ pyrochlore ceramic for Faraday rotation

To design an innovative magneto-optical material aimed at a large Verdet constant coincides with the development trend of state-of-the-art modern optical devices. In this work, a magneto-optical transparent Pr₂Zr₂O₇ ceramic with pyrochlore structure was successfully fabricated by vacuum sintering plus hydrogen reduction for the first time to our knowledge. The two- and three-dimensional images observed on the laser scanning confocal microscopy reveal that the grain-boundary dent depth of the polished Pr₂Zr₂O₇ ceramic is only ∼1.6 µm upon thermal etching at a high temperature of 1675°C for 2 h, showing excellent heat-resistance ability. The crystal-clear Pr₂Zr₂O₇ ceramic has a high in-line transmittance of ∼71.6% at 780 nm (∼92.3% of the theoretical value), a high refractive index of ∼2.1, and an effective magnetic moment of ∼5.28 <i>µ</i> _B. In the visible region, the O^2- polarizability and optical basicity of the Pr₂Zr₂O₇ compound generally retain constants around 2.37 ± 0.07 ų and 0.965 ± 0.015, respectively. The magneto-optical transparent Pr₂Zr₂O₇ ceramic exhibits high Verdet constants of -336 ± 4, -208 ± 3, -108 ± 1, and -48 ± 2 rad·T^-1·m^-1 at 515, 635, 780, and 1064 nm, respectively, which were ∼1.55-fold higher than the commercial Tb₃Ga₅O₁₂ single crystal. Our developed new-type ceramic material has excellent potential application for Faraday rotation.