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Abstract Acting like thermal resistances, ferroelectric domain walls can be manipulated to realize dynamic modulation of thermal conductivity (k), which is essential for developing novel phononic circuits. Despite the interest, little attention has been paid to achieving room‐temperature thermal modulation in bulk materials due to challenges in obtaining a high thermal conductivity switching ratio (khigh/klow), particularly in commercially viable materials. Here, room‐temperature thermal modulation in 2.5 mm‐thick Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN–xPT) single crystals is demonstrated. With the use of advanced poling conditions, assisted by the systematic study on composition and orientation dependence of PMN–xPT, a range of thermal conductivity switching ratios with a maximum of ≈1.27 is observed. Simultaneous measurements of piezoelectric coefficient (d33) to characterize the poling state, domain wall density using polarized light microscopy (PLM), and birefringence change using quantitative PLM reveal that compared to the unpoled state, the domain wall density at intermediate poling states (0<d33<d33,max) is lower due to the enlargement in domain size. At optimized poling conditions (d33,max), the domain sizes show increased inhomogeneity that leads to enhancement in the domain wall density. This work highlights the potential of commercially available PMN–xPT single crystals among other relaxor‐ferroelectrics for achieving temperature control in solid‐state devices.
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Unlocking Electrostrain in Plastically Deformed Barium Titanate
Abstract Achieving substantial electrostrain alongside a large effective piezoelectric strain coefficient (d33*) in piezoelectric materials remains a formidable challenge for advanced actuator applications. Here, a straightforward approach to enhance these properties by strategically designing the domain structure and controlling the domain switching through the introduction of arrays of ordered {100}<100> dislocations is proposed. This dislocation engineering yields an intrinsic lock‐in steady–state electrostrain of 0.69% at a low field of 10 kV cm−1without external stress and an output strain energy density of 5.24 J cm−3in single‐crystal BaTiO3, outperforming the benchmark piezoceramics and relaxor ferroelectric single‐crystals. Additionally, applying a compression stress of 6 MPa fully unlocks electrostrains exceeding 1%, yielding a remarkabled33* value over 10 000 pm V−1and achieving a record‐high strain energy density of 11.67 J cm−3. Optical and transmission electron microscopy, paired with laboratory and synchrotron X‐ray diffraction, is employed to rationalize the observed electrostrain. Phase‐field simulations further elucidate the impact of charged dislocations on domain nucleation and domain switching. These findings present an effective and sustainable strategy for developing high‐performance, lead‐free piezoelectric materials without the need for additional chemical elements, offering immense potential for actuator technologies.
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- Award ID(s):
- 2133373
- PAR ID:
- 10592731
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 36
- Issue:
- 52
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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