Achieving large electric-field-induced strain in lead-free piezoelectrics

• Main Authors: Patrick Tung, John E. Daniels, Márton Major, Deborah Schneider, Richard Chen, Haosu Luo, Torsten Granzow
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2019-05-01
• Series: Materials Research Letters
• Subjects: Piezoelectricity; relaxor ferroelectrics; field-induced phase transitions
• Online Access: http://dx.doi.org/10.1080/21663831.2019.1570979

Lead-free piezoelectric single crystals of Fe-doped 0.95(Bi1/2Na1/2)TiO3-0.05BaTiO3 are shown to combine multiple mechanisms for high strain and an effective piezoelectric coefficient of up to 3260 pm/V. This is explained based on the analysis of superstructure reflections from diffuse synchrotron x-ray scattering. It depends on three factors: (1) the stabilization of a local tetragonal structure by (Fe’- $ V_O^{ \bullet \bullet } $ )• defect dipoles, (2) the reversible creation of a morphotropic phase boundary under field, and (3) the field-induced reversible transition between a short-range ordered relaxor and a long-range ordered ferroelectric state.