Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study
Precursor elastic effects are investigated in a displacive anharmonic spring model and shown to extend greatly into the paraelastic phase. Weak precursor effects can be detected near 2T_{tr}, where T_{tr} is the ferroelastic transition temperature. The precursor effects become strong at T<1.7T_{t...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2024-03-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.6.013232 |
| _version_ | 1797210267129479168 |
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| author | Guangming Lu Francesco Cordero Kimura Hideo Xiangdong Ding Zhijun Xu Ruiqing Chu Christopher J. Howard Michael A. Carpenter Ekhard K. H. Salje |
| author_facet | Guangming Lu Francesco Cordero Kimura Hideo Xiangdong Ding Zhijun Xu Ruiqing Chu Christopher J. Howard Michael A. Carpenter Ekhard K. H. Salje |
| author_sort | Guangming Lu |
| collection | DOAJ |
| description | Precursor elastic effects are investigated in a displacive anharmonic spring model and shown to extend greatly into the paraelastic phase. Weak precursor effects can be detected near 2T_{tr}, where T_{tr} is the ferroelastic transition temperature. The precursor effects become strong at T<1.7T_{tr}. Two effects were identified in our two-dimensional model: the symmetry-breaking strain e_{3} (ɛ_{xy}) leads to softening of the elastic modulus C_{33}, while the nonsymmetry-breaking strain e_{1}+e_{2} (ɛ_{xx}+ɛ_{yy}) leads to hardening of C_{11}. The strain e_{3} is proportional to the order parameter and scales as |e_{1}+e_{2}|∼e_{3}^{2}. The temperature evolutions of the elastic moduli are surprisingly well described by power laws and Vogel-Fulcher equations. The power-law exponents are ∼−0.5 for ΔC_{33} and ∼−1 for ΔC_{11}, Δ(C_{11}+C_{12}) and Δ(C_{11}−C_{12}). The Vogel-Fulcher temperatures are very similar, while the Vogel-Fulcher energies differ between the excess elastic moduli. The origin of the precursor effect is the evolution of short-range order in the paraelastic phase which gives rise to a characteristic local nanostructure. In the case of the symmetry-breaking strain, this microstructure resembles dynamical twinning patterns corresponding to the ferroelastic nanostructure, which weakens the material. In the case of the nonsymmetry-breaking strain, we find density fluctuations which make the material harder. |
| first_indexed | 2024-04-24T10:07:52Z |
| format | Article |
| id | doaj.art-d5643ad79ab04652a5ed385161cbf163 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:07:52Z |
| publishDate | 2024-03-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-d5643ad79ab04652a5ed385161cbf1632024-04-12T17:39:55ZengAmerican Physical SocietyPhysical Review Research2643-15642024-03-016101323210.1103/PhysRevResearch.6.013232Elastic precursor softening in proper ferroelastic materials: A molecular dynamics studyGuangming LuFrancesco CorderoKimura HideoXiangdong DingZhijun XuRuiqing ChuChristopher J. HowardMichael A. CarpenterEkhard K. H. SaljePrecursor elastic effects are investigated in a displacive anharmonic spring model and shown to extend greatly into the paraelastic phase. Weak precursor effects can be detected near 2T_{tr}, where T_{tr} is the ferroelastic transition temperature. The precursor effects become strong at T<1.7T_{tr}. Two effects were identified in our two-dimensional model: the symmetry-breaking strain e_{3} (ɛ_{xy}) leads to softening of the elastic modulus C_{33}, while the nonsymmetry-breaking strain e_{1}+e_{2} (ɛ_{xx}+ɛ_{yy}) leads to hardening of C_{11}. The strain e_{3} is proportional to the order parameter and scales as |e_{1}+e_{2}|∼e_{3}^{2}. The temperature evolutions of the elastic moduli are surprisingly well described by power laws and Vogel-Fulcher equations. The power-law exponents are ∼−0.5 for ΔC_{33} and ∼−1 for ΔC_{11}, Δ(C_{11}+C_{12}) and Δ(C_{11}−C_{12}). The Vogel-Fulcher temperatures are very similar, while the Vogel-Fulcher energies differ between the excess elastic moduli. The origin of the precursor effect is the evolution of short-range order in the paraelastic phase which gives rise to a characteristic local nanostructure. In the case of the symmetry-breaking strain, this microstructure resembles dynamical twinning patterns corresponding to the ferroelastic nanostructure, which weakens the material. In the case of the nonsymmetry-breaking strain, we find density fluctuations which make the material harder.http://doi.org/10.1103/PhysRevResearch.6.013232 |
| spellingShingle | Guangming Lu Francesco Cordero Kimura Hideo Xiangdong Ding Zhijun Xu Ruiqing Chu Christopher J. Howard Michael A. Carpenter Ekhard K. H. Salje Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study Physical Review Research |
| title | Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study |
| title_full | Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study |
| title_fullStr | Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study |
| title_full_unstemmed | Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study |
| title_short | Elastic precursor softening in proper ferroelastic materials: A molecular dynamics study |
| title_sort | elastic precursor softening in proper ferroelastic materials a molecular dynamics study |
| url | http://doi.org/10.1103/PhysRevResearch.6.013232 |
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