Properties of Magnetic Shape Memory Alloys in Martensitic Phase

Abstract

The Heusler alloys that exhibit reversible martensitic transition show multifunctional properties including magnetic shape memory effect. The properties of two kinds of magnetic shape memory alloys are studied, where magnetic field-induced strain is driven by two different mechanisms. The properties differ in martensitic phase with composition and thus they are studied in martensitic phase. The crystal structure (Xray diffraction), magnetic behaviour (SQUID), transport analysis (four-probe method), magneto-transport trend (up to 8 T), magnetocaloric effect (around room-temperature), electronic structure (X-ray photoelectron spectroscopy and ab initio calculation), surface characterization (ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy) are discussed for the matensitic phase. Analysis of the properties reveals alloys with possible applicability at room temperature with low magnetic field.

Pair distribution function study ofNi2MnGamagnetic shape memory alloy: Evidence for the precursor state of the premartensite phase

“…A similar difference, though with a smaller value of thermal hysteresis (∼2.4 K), in the characteristic premartensite phase transition temperatures reveals the first-order character of the FM austenite-to-FM premartensite phase transition also. All the characteristic transition temperatures, determined from the M(T) and χ (T) plots, are in good agreement with those reported in the literature [37,44,57,60,81,86,97,98,[100][101][102].…”

“…Commun. 8, 1006(2017], there is a need to revisit the precursor effects in these materials. We present here evidence for the existence of a precursor state of the premartensite phase in Ni 2 MnGa MSMA by atomic pair distribution function analysis of high-energy, high-flux, and high-Q synchrotron x-ray powder diffraction data.…”

Structural, Thermal and Magnetic Characterization of Polycrystalline Ni-Mn-Ga Ferromagnetic Shape Memory Alloys

“…This reorientation can be produced by stress and/or the application of a magnetic field. The complex behavior exhibited by these materials is a consequence of the strong coupling between magnetism and the structure which is driven by the martensitic transition 1,5,6 .…”