Ferroelectric-to-relaxor Crossover in (1-x) BaTiO3-xBiYbO3 (0≤ x≤ 0.08) ceramics

Dense (1-x)BaTiO3-xBiYbO3 (BBTYb) ceramics were fabricated by the solid state reaction method. According to X-ray diffraction data, the average crystal symmetry of x ≤ 0.04 ceramics is described by the non-centro symmetric tetragonal P4mm space group, whereas the average crystal symmetry of x ≥ 0.06 ceramics is better described by the centrosymmetric cubic Pmm space group. Raman spectroscopy supports a change in the average crystal symmetry at x ≥ 0.06, but also reveals differences in the local crystal structure for x ≤ 0.04. In this compositional range, BBTYb ceramics undergo a so-called ferroelectric-to-relaxor crossover, which is a manifestation of the continuous modification of local structure. Weak-relaxor behavior was observed in x ≥ 0.06 ceramics, for which the local crystal symmetry departs from cubic, as indicated by the presence of Raman spectra.