Thermally Induced Evolution of the Local Structural Behavior in BiFeO 3 ‐BaTiO 3 ‐Based Ceramics

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ABSTRACT The environmental urgency to replace toxic lead‐based piezoelectrics like Pb(Zr,Ti)O 3 has driven the development of lead‐free alternatives such as BiFeO 3 –BaTiO 3 ceramics. While macroscopic structural optimization has yielded promising electrostrain performance, the role of the local structure remains underexplored. This study presents the first thermally induced investigation of the local structural behavior in Nd(Mg 2/3 Nb 1/3 )O 3 ‐doped BiFeO 3 –BaTiO 3 ceramics using synchrotron x‐ray pair distribution function (XPDF) analysis coupled with Raman spectroscopy. XPDF analysis reveals a dominant short‐range tetragonal phase that undergoes a local phase transition near 200°C, marked by changes in lattice distortion and tetragonality. Complementary Raman spectroscopy and principal component analysis confirm spectral anomalies and phonon mode coupling in the same temperature range, indicating a potential local structural transition. These findings provide critical insights into the temperature stability and local phase dynamics of BiFeO 3 ‐based ceramics, offering a pathway to high‐temperature lead‐free piezoelectric applications.