- Ren, Yifeng;
- Li, Jiayi;
- Zhao, Yunlei;
- Ciston, Jim;
- Bustillo, Karen;
- Zhang, Ruopeng;
- Dong, Hongliang;
- Chen, Zhiqiang;
- Minor, Andrew M;
- Deng, Yu
In BaTiO3 single crystals, we observed a strain-driven phase transition from the tetragonal phase to the tetragonal-orthorhombic phase boundary which can be introduced by slow cycling compressions (a loading of up to 0.5 GPa, strain rate of 10-4 s-1, and 100 cycles) at room temperature. Different from the well-known tetragonal to cubic phase transition under stress (∼2 GPa), it only takes place locally around bent 90° domain walls. The inhomogeneous local stress and electrical fields as well as the mobile point defect pinning effect contribute to the phase re-entrance. Through comparison experiments by in situ synchrotron x-ray diffraction, Raman scattering, and (scanning) transmission electron microscopy, we explored the phase transition mechanism. Based on that, we developed a mechanical method to obtain well-stabilized high-density thermotropic phase boundary structures (with tetragonal, orthorhombic, and bridging monoclinic phases) in BaTiO3 for potential applications.