Optimization of PbTiO₃Single Crystals with Flux and Laser Floating Zone Method

PbTiO₃is an established high temperature ferroelectric and component of multiferroic devices. Single crystal growth of clean PbTiO₃has largely been limited to flux growth, in part due to the volatility of PbTiO₃near the melting point. We demonstrate the ability to grow single crystals of PbTiO₃using the laser diode floating zone technique. Crystal quality is examined using Laue, powder, and single crystal X-ray diffraction. Low temperature specific heat and annealing experiments using thermogravimetric analysis/differential thermal analysis were used to compare the disorder and vacancies generated in the laser diode floating zone with those produced by flux growth. Samples grown using the floating zone method showed minimal oxygen deficiency, while samples grown via flux had a higher density of vacancies and metal impurities (determined using glow discharge mass spectrometry), resulting in room temperature ferromagnetic behavior. The use of laser diodes as a heating source in the optical floating zone technique is essential in the stability of the zone growth and could be applied for production and zone refinement of other volatile materials.