Crystal growth of pyrochlore pr2zr2o7 and its la and nd analogs using flux method

Abstract

We report the growth of millimetre-sized single crystals of Pr2Zr2O7 using PbO-PbF2 flux in the temperature range 1250 °C to 1350 °C, significantly below the order–disorder transition (∼2000°C). The applicability of this flux for the growth of pyrochlores Nd2Zr2O7 and La2Zr2O7 is also demonstrated. The grown crystals exhibit well-formed octahedral shape and high structural quality as confirmed by high-resolution TEM, FESEM, Raman, and magnetic susceptibility measurements. Analysis of the lattice constants and magnetic susceptibilities of the grown crystals reveals that even the best-grown crystals exhibit slight antistuffing (up to 5 at.%); i.e., with Pr/Zr ratios <1. Polycrystalline samples with varying levels of stuffing and antistuffing (Pr/Zr ≡2+x/2−x; −0.1≤x≤0.1) were used to establish a correlation between lattice constants of the grown crystals and their Pr : Zr composition. Our study establishes the suitability of PbO-PbF2 flux for growing high-quality pyrochlore zirconates, offering an alternative to the high temperature (>2500 °C) xenon-lamp-based floating-zone method previously employed for these materials.