Precursor of the premartensite in Ni2MnGa magnetic shape memory alloy: A pair distribution function study

Abstract

Precursor phenomena observed prior to the martensite phase transition plays a critical role towards the understanding of important technological properties of shape memory and magnetic shape memory alloys (MSMAs). The premartensite (PM) phase, considered as the precursor state of the martensite is proven to be a thermodynamically stable phase recently (Nature Commun. 8, 1006 (2017)), necessitates a critical investigation of precursor effects in these materials. We present here an evidence for the existence of a precursor state of the PM phase in Ni2MnGa MSMA using high energy synchrotron pair distribution function (PDF) study. The precursor state embedded within the austenite matrix in the short-range ordered (SRO) regime starting from far above the actual PM phase transition. The presence of such SRO precursor states of the PM phase produces strains which couple with the ferromagnetic (FM) order parameter around TC leading to first order character of the paramagnetic to FM phase transition.

References in corpus (14)

• PDFgetX3: A rapid and highly automatable program for processing powder diffraction data into total scattering pair distribution functions
• Direct observation of the formation of polar nanoregions in Pb(Mg${}_{1/3}$Nb${}_{2/3}$)O${}_3$ using neutron pair distribution function analysis
• First-principles study of lattice instabilities in the ferromagnetic martensite Ni${}_2$MnGa
• Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic $N{i}_{2}MnGa$
• Lattice dynamics and correlated atomic motion from the atomic pair distribution function
• Premartensite to martensite transition and its implications on the origin of modulation in Ni2MnGa ferromagnetic shape memory alloy
• Residual stress induced stabilization of martensite phase and its effect on the magneto-structural transition in Mn rich Ni-Mn-In/Ga magnetic shape memory alloys
• A high resolution synchrotron x-ray powder diffraction study of the incommensurate modulation in the martensite phase of Ni2MnGa: Evidence for nearly 7M modulation and phason broadening
• Robust Bain distortion in the premartensite phase of platinum substituted Ni2MnGa magnetic shape memory alloy
• Modulated structure in the martensite phase of Ni1.8Pt0.2MnGa: a neutron diffraction study
• Temperature dependence of the anomalous Nernst effect in Ni${}_2$MnGa shape memory alloy
• A new paradigm for modulated phases in multi-stage structural transformations
• Incommensurate modulations in stoichiometric Ni2MnGa ferromagnetic shape memory alloy: An overview
• Unusual Strain glassy phase in Fe doped Ni${}_2$Mn${}_{1.5}$In${}_{0.5}$

Cited by in corpus (1)

• Robust evidence for the stabilization of the premartensite phase in Ni-Mn-In magnetic shape memory alloys by chemical pressure