Electrochemical single crystal growth of Tb24O44 microparticles

Single crystals of non-stoichiometric terbium oxide Tb24O44 (≡TbO1.833) were successfully grown by the dc electrolysis of the Tb3+ ion conducting Tb2(MoO4)3 solid electrolyte at the moderate conditions of 3 V at 900 °C. Electron diffraction patterns for each particle grown clearly indicate that the particles were single crystals of the β2-phase of high quality Tb24O44 (≡TbO1.833). Tb24O44 is triclinic of space group P1¯ with a = 6.49 Å, b = 12.27 Å, c = 12.43 Å, α = 78.51°, β = 99.82° and γ = 71.12°. The crystal size can be intentionally controlled by adjusting the electrolysis period: the average particle sizes were 0.40, 0.65 and 1.52 μm for 1, 2 and 4 weeks electrolysis, respectively.