Strain-induced dimensionality crossover of precursor modulations in Ni2MnGa
- Beijing Inst. of Technology, Beijing (China)
- Univ. of Science and Technology Beijing (China)
- Pennsylvania State Univ., University Park, PA (United States)
- Carnegie Inst. of Washington, Argonne, IL (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- General Research Inst. for Nonferrous Metals, Beijing (China)
- Carnegie Inst. of Washington, Argonne, IL (United States); Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)
Precursor modulations often occur in functional materials like magnetic shape memory alloys, ferroelectrics, and superconductors. In this letter, we have revealed the underlying mechanism of the precursor modulations in ferromagnetic shape memory alloys Ni2MnGa by combining synchrotron-based x-ray diffraction experiments and first-principles phonon calculations. We discovered the precursor modulations along [011] direction can be eliminated with [001] uniaxial loading, while the precursor modulations or premartensite can be totally suppressed by hydrostatic pressure condition. The TA2 phonon anomaly is sensitive to stress induced lattice strain, and the entire TA2 branch is stabilized along the directions where precursor modulations are eliminated by external stress. Furthermore, our discovery bridges precursor modulations and phonon anomalies, and sheds light on the microscopic mechanism of the two-step superelasticity in precursor martensite.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF); National Basic Research Program of China; Argonne National Laboratory, Advanced Photon Source
- Grant/Contract Number:
- AC02-06CH11357; 2012CB619405; DMR-1006557; DMR-1310289; SC0001057; NA0001974; FG02-99ER45775
- OSTI ID:
- 1242401
- Alternate ID(s):
- OSTI ID: 1226695
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 2; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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