Yttria-stabilized zirconia is known to not be completely stabilized in the pure cubic YSZ phase up to temperatures above 1000 °C (Ref. and publications therein), commonly used abbreviations in conjunction with yttria-stabilized zirconia are: The thermal expansion coefficients depends on the modification of zirconia as follows: By the addition of yttria to pure zirconia (e.g., fully stabilized YSZ) Y ions replace Zr on the cationic sublattice. Thereby, oxygen vacancies are generated due to charge neutrality: formula_4 with formula_5, meaning two Y ions generate one vacancy on the anionic sublattice. This facilitates moderate conductivity of yttrium stabilized zirconia for O ions (and thus
Cubic zirconia exceeded that of earlier synthetics, such as synthetic strontium titanate, synthetic rutile, YAG (yttrium aluminium garnet) and GGG (gadolinium gallium garnet). Some of the earliest research into controlled single-crystal growth of cubic zirconia occurred in 1960s France, much work being done by Y. Roulin and R. Collongues. This technique involved molten zirconia being contained within a thin shell of still-solid zirconia, with crystal growth from the melt. The process was named "cold crucible", an allusion to the system of water cooling used. Though promising, these attempts yielded only small crystals. Later, Soviet scientists under V. V. Osiko at the Lebedev