Interplay between ferroelectric and quantum paraelectric instabilities in Eu0.7Ba0.3TiO3 Perovskite oxide: Defect dipoles and ferroelectric instability induced by oxygen vacancies

Investigation of intrinsic response and proper selection/tailoring of perovskite oxides is challenging and essential to understand the origin of various instabilities. For this purpose, Eu0.7Ba0.3TiO3-δ is shown to be a prime candidate. Coexistence of quantum paraelectric and ferroelectric instabilities with Ba substitution and variation of oxygen vacancies has been demonstrated in a specifically chosen composition. Random distribution of Ba2+ ions in a stoichiometric composition brings the system toward phase boundary. Interestingly, in the space charge unactivated temperature regime, the role of intentionally introduced oxygen vacancies is to induce ferroelectric character through the formation of local defect dipoles.