Flux growth and characterisation of rhombohedral BiFeO3-PbTiO3 single crystals
Single crystals of bismuth ferrite-lead titanate (BFPT) were grown using a flux method. Starting from bismuth ferrite, we added lead titanate, to produce a range of compositions within the BiFeO3-PbTiO3 solid solution, through to the morphotropic phase boundary (MPB). Using a PbO:Bi2O3 flux, and a cooling rate of 0.5°C/h over the temperature range where crystal growth is expected, our aim was to produce highly pure, good size, crack free rhombohedral single crystals. Energy dispersive X-ray analysis (EDX) and scanning electron microscopy (SEM) was used to determine the chemical composition and structure of the crystals, and powder X-ray diffraction (XRD) confirmed the crystal structure.
Structure property relations in BiFeO3/BaTiO3 solid solutions
BiFeO3, when forming a solid solution with BaTiO3, shows structural transformations over the entire compositional range. Above 70 mole % of BiFeO3 the structure is rhombohedral and below 4 mole %, it is tetragonal. In between the structure is cubic. The ferroelectric TC decreases with increasing composition of BaTiO3 and a relatively small relaxation is observed. Impedance measurements showed a structural dependence and analysis of which has clearly shown that the capacitance observed is from the bulk of the sample. Relaxation time (τ) of BiFeO3 was estimated using the relaxation times of the intermediate compositions. Magnetization measurements showed field induced ferromagnetism. As the structure becomes cubic with increasing concentration of BaTiO3, paramagnetism sets in, as evidenced by the electron spin resonance spectra.
Body sculpturing.
Significant improvements in body contour can be accomplished by surgical procedures having reliable, predictable results. Similar to the modern sculptor of inanimate art forms, plastic surgeons have utilized new materials and devised new techniques to achieve aesthetic improvement of the face, trunk, and extremities. The goals of the surgical sculptor are perhaps more challenging than those of the pure artistic sculptor, not only because they must result in improved appearance but also because the surgeon is limited at all times by considerations of regional anatomy, the availability of viable tissue materials, and the safety of his patient.