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Stability of morphotropic (110) oriented 0.65PMN-0.35PT single crystals
Gaël Sébald1, Laurent Lebrun, Daniel Guyomar
1Electrical Engineering Laboratory, Insa de Lyon, 69621 Villeurbanne, France. gael.sebald@insalyon.fr
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
|December 17, 2004
Summary
This study investigates lead magnesium niobate-lead titanate (PMN-PT) single crystals, finding their electromechanical properties are maximized at a specific phase ratio. Performance is limited by temperature-induced phase transitions and high stress, but crystals show good aging stability.
Area of Science:
- Materials Science
- Solid State Physics
- Crystallography
Background:
- Lead magnesium niobate-lead titanate (PMN-PT) single crystals are advanced piezoelectric materials.
- Understanding their electromechanical properties under various conditions is crucial for device applications.
Purpose of the Study:
- To investigate the electromechanical properties of PMN-PT single crystals (x=0.35) under external disturbances.
- To determine performance-limiting factors and stability.
- To correlate electromechanical properties with phase ratios.
Main Methods:
- Polarization path optimization.
- X-ray diffraction for phase ratio analysis.
- Testing under temperature, stress, electric field, and aging conditions.
Main Results:
- Maximum electromechanical properties correlate with a minimum rhombohedral/tetragonal phase ratio.
- A temperature-induced phase transition at 80°C decreases electromechanical coupling from 85% to 50%, with recovery upon cooling.
- Depoling occurs above 30 MPa stress.
- Crystals exhibit good aging stability, with minor increases in mechanical and dielectric losses.
Conclusions:
- The phase ratio is a critical factor for optimizing electromechanical properties in PMN-PT crystals.
- Temperature and stress are significant performance limitations.
- PMN-PT crystals demonstrate robust stability under aging and AC electric fields, making them suitable for demanding applications.