Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
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http://dx.doi.org/10.1126/science.1177046 | DOI Listing |
Nature
January 2025
Department of Materials Engineering, Indian Institute of Science, Bangalore, India.
Piezoelectric materials directly convert between electrical and mechanical energies. They are used as transducers in applications such as nano-positioning and ultrasound imaging. Improving the properties of these devices requires piezoelectric materials capable of delivering a large longitudinal strain on the application of an electric field.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Physics, Indian Institute of Technology Banaras Hindu University, Indian Institute of Technology (Banaras Hindu University), Department of Physics, Varanasi, Varanasi, Uttar Pradesh, 221005, INDIA.
In the present work, we reinvestigate the atomic ordering of a Pb-free Morphotropic Phase Boundary (MPB) composition viz., K0.5Na0.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Center for Semiconductor Technology Convergence, Department of Electrical Engineering, Pohang University of Science and Technology, Cheongam-ro 77, Nam-gu, Pohang, Gyeongbuk 37673, South Korea.
A novel approach to delicately control the phase of a ferroelectric has been developed using a continuous-wave laser scanning annealing (CW-LSA) process. After proper process optimization, the equivalent oxide thickness (EOT) of 3.5 Å with a dielectric constant (κ) of 68 Å is achieved from HZO in a metal-ferroelectric-metal (MFM) capacitor structure.
View Article and Find Full Text PDFHeliyon
June 2024
Signals, Systems and Components Laboratory (LSSC), Faculty of Sciences and Technologies of Fez, Sidi Mohamed Ben Abdellah University, B.P. 2022, Fez, Morocco.
The solid-state reaction technique was employed to synthesize lead-free ceramics, specifically (1-x-y)(NaBi)TiO-xBaTiO-y(KBi)TiO. For attaining a pure perovskite phase, it was found that the optimal calcination temperature is 1000 °C, maintained for a duration of 4 h. Through X-ray diffraction (XRD) analysis, the morphotropic phase boundary (MPB) was detected in (1-x-y)NBT-xBT-yKBT ceramics for certain molar compositions, specifically in 0.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Physics, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand.
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