DIFFUSE PHASE-TRANSFORMATIONS IN NEODYMIUM-DOPED BATIO3 CERAMICS

Phase transitions in BaTiO//3 doped with neodymium have been studied using temperature-capacitance measurements, differential scanning calorimetry, X-ray powder diffraction and electron paramagnetic resonance spectroscopy. The coexistence of a para-electric cubic phase with the ferroelectric tetragonal and orthorhombic phases is noticed within the temperature range corresponding to the stability region of the latter phases in undoped BaTiO//3. The broad maximum in the effective dielectric constant shifts to lower temperature with increase in neodymium content. The heat of transformation measured at the Curie point tends to zero above 3. 5 at% Nd and the phase transition gradually approaches the second order. These are characteristics of a diffuse phase transformation.