Top-seeded solution growth of SrTiO3 crystals and phase diagram studies in the SrO–TiO2 system

Abstract

The TiO 2 rich part of the (1 − x) SrO + x TiO 2 phase diagram 0.5 ≤ x ≤ 1.0 was redetermined and the eutectic point between SrTiO 3 and TiO 2 was found at x eut = 0.7700 ± 0.0001; T eut = (1449 ± 3) • C. From TiO 2 rich melt solutions, x = 0.75 centimetersized single crystals could be grown. The best crystals with etch pit density < 2 × 10 4 /cm 2 were obtained for growth directions 110 and 100 . AFM investigation of the interface reveals layer-by-layer growth.

Temperature-dependent optical absorption of SrTiO3

“…At the melting point (2350 K), the total energy of all photons with an energy higher than the band gap is about J m, which is 14.5% of the total radiated energy. If the crystal is not grown from the melt but from self flux with slow cooling, it is possible to grow a straight cylinder below 1808 K (). In this case, the energy of photons absorbable by excitation over the band gap is J m, which is about 0.35% of the total black body emission and about 121 times less than the absorbable energy at 2350 K. This difference and the lower IR absorption apparently allows stable growth and improved crystal quality ().…”

Particle Surface Softening as Universal Behaviour during Flash Sintering of Oxide Nano-Powders

“…Using the measured (not calculated) published data for 3YSZ [19,20] and SrTiO 3 [8], where flash event durations were clearly indicated, their properties [22,23,24,25,26] and flash sintering conditions, together with their corresponding calculated temperature, T cont , are listed in Table 1. In both oxides, the temperatures at the particle contacts are far above their corresponding melting points, i.e., 3114 °C versus 2680 °C for 3YSZ, and 4216 °C versus 2080 °C for SrTiO 3 , and confirm the possibility for local melting/surface softening at these loci.…”

On melt solutions for the growth of CaTiO3 crystals

“…However it is a drawback of all these solvents that they add foreign ions to the melts that may enter up to a few percents in the crystal structure of the solute CaTiO 3 . In recent studies the growth of high quality SrTiO 3 proved possible from an excess of TiO 2 as solvent [16,17]. The eutectic temperature of SrTiO 3 /TiO 2 T eut = 1722 ± 3 K is significantly lower than the congruent melting point of SrTiO 3 T f = 2352±20 K. Corresponding literature data for the CaTiO 3 /TiO 2 eutectic range from T eut = 1690 K [6] to T eut = 1726 K [8], which indicates a less significant lowering of the liquidus temperature at the eutectic composition.…”