Seminar LMGP - 19/01/2016 - Dr. Šarūnas Bagdzevičius - Misfit and chemical strain effects in incipient ferroelectric SrTiO3

Post-doc in LMGP, Grenoble-INP, France - Work done in Vilnius University, Lithuania and EPFL, Switzerland

Misfit and chemical strain effects in incipient ferroelectric SrTiO₃

Abstract

Incipient ferroelectric SrTiO₃ (STO) is a model system for investigation of ferroelectric and structural phase transitions because Goldschmidt tolerance factor t ≈ 1, this means that both instabilities are competing in sufficiently close temperature ranges and both are rather sensitive to chemical and misfit strain. STO is well known and widely investigated perovskite material and recently again attracted attention as tunable high-k material for reconfigurable radio and microwave telecommunication devices, and possible piezoelectric applications. For enhancement of piezoelectric effect there is effort to induce so called “relaxor ferroelectric” state in the STO, which could benefit from possible giant piezoelectric response as in Pb-based relaxor piezoelectrics (PMN-PT etc.). In this talk I will present the latest research results of strain (chemical and misfit) engineered STO ceramics and epitaxial thin films towards induced ferroelectricity and enhanced piezoelectricity.