Strain-induced dimensionality crossover of precursor modulations in Ni2MnGa

Zhihua Nie, Yandong Wang, Shunli Shang, Qiaoshi Zeng, Yang Ren, Dongmei Liu, Wenge Yang, Yi Wang, Zi Kui Liu

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2 Scopus citations

Abstract

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. Our discovery bridges precursor modulations and phonon anomalies, and sheds light on the microscopic mechanism of the two-step superelasticity in precursor martensite.

Original languageEnglish (US)
Article number021910
JournalApplied Physics Letters
Volume106
Issue number2
DOIs
StatePublished - Jan 12 2015

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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