Influence of structural transition on transport and optical properties of Ni2MnGa alloy

Yinqing, Zhou; Jin, Xuesong; Xu, Huibin; Kudryavtsev, Y. V.; Lee, Y. P.; Rhee, Joo Yull

doi:10.1063/1.1478131

Cited by 28 publications

(14 citation statements)

References 19 publications

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“…The transport property of Ni 2 MnGa is dominated by electron-magnon and electron-phonon scattering 47 . The resistivity behaviour of Ni 2+x Mn 1-x Ga is metallic with sudden increase in resistivity at the martensitic transition (see Biswas et al 30 , figure 1 a).…”

Section: Transport Analysismentioning

confidence: 99%

Properties of Magnetic Shape Memory Alloys in Martensitic Phase

Maji¹

2017

Current Science

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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.

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Section: Transport Analysismentioning

confidence: 99%

Properties of Magnetic Shape Memory Alloys in Martensitic Phase

Maji¹

2017

Current Science

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“…Moreover, 10 M214 M is accompanied by a decrease in r in both the forward and the reverse transformations. Since both IMTs have a large temperature hysteresis, these unusual features of the transport properties could be explained by assuming that electron-phonon and electron-magnon contributions to the electrical resistivity depend considerably on temperature [15] but to different extent for the different martensitic phases.…”

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confidence: 99%

Intermartensitic phase transformations in Ni–Mn–Ga studied under magnetic field

Chernenko

Cesari

Ховайло

et al. 2005

Journal of Magnetism and Magnetic Materials

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“…The time-resolved x-ray diffraction was performed at an x-ray energy of 5 keV using a synchrotron slicing source (200 ph/pulse, 2 kHz and 1.2 %bw) as probe and an 800 nm, 120 fs 1 kHz p-polarized laser pulse at 12 o incidence as pump (absorption length δ = 20 nm [20]), giving a total time resolution of 200 fs [21]. The x-ray spot was focused horizontally to 400 µm, vertically to 10 µm and the gracing incidence angle was set to 0.65 (absorption length α = 20 nm [22]) to match the penetration depth of the x-ray probe to the laser pump.…”

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confidence: 99%

“…The MT structure is modulated [7, 9,19] but unlike the single modulation wavevector q = [ξξ0] with ξ = 0.428 of single crystal Ni 2 MnGa, the film has two modulation wavevectors with ξ = 0.311(2) and 0.51(1) in reciprocal lattice units of the orthorhombic lattice. The first wavevector is close to the ξ = 0.308 found for the 7M structure [8].The time-resolved x-ray diffraction was performed at an x-ray energy of 5 keV using a synchrotron slicing source (200 ph/pulse, 2 kHz and 1.2 %bw) as probe and an 800 nm, 120 fs 1 kHz p-polarized laser pulse at 12 o incidence as pump (absorption length δ = 20 nm [20]), giving a total time resolution of 200 fs [21]. The x-ray spot was focused horizontally to 400 µm, vertically to 10 µm and the gracing incidence angle was set to 0.65 o…”

mentioning

confidence: 99%

Structural and magnetic dynamics in the magnetic shape-memory alloyNi2MnGa

et al. 2014

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Magnetic shape memory Heusler alloys are multiferroics stabilized by the correlations between electronic, magnetic and structural order. To study these correlations we use time resolved x-ray diffraction and magneto-optical Kerr effect experiments to measure the laser induced dynamics in a Heusler alloy Ni2MnGa film and reveal a set of timescales intrinsic to the system. We observe a coherent phonon which we identify as the amplitudon of the modulated structure and an ultrafast phase transition leading to a quenching of the incommensurate modulation within 300 fs with a recovery time of a few ps. The thermally driven martensitic transition to the high temperature cubic phase proceeds via nucleation within a few ps and domain growth limited by the speed of sound. The demagnetization time is 320 fs, which is comparable to the quenching of the structural modulation.Multiferroic materials which exhibit large responses to electromagnetic and stress fields are of great interest for novel technical applications. To guide their rational design the microscopic origin of their functional properties must be understood which requires methods that can disentangle the interplay between electronic, magnetic and structural degrees of freedom. A prototypical example is the optimization of ferromagnetic X 2 YZ Heusler alloys, where one class shows novel functional properties such as magnetic shape memory and magnetocaloric effects due to the coexistence of ferromagnetism and a structural martensitic (MT) transition [1], and another class is half-metallic and suitable for spintronic applications [2]. Ni 2 MnGa is the classical Heusler magnetic shape memory alloy with a magnetically induced strain of up to 10% arising from the interplay between magnetic and structural domains in the twinned low temperature MT phase [1,[3][4][5]. The structure of the MT phase changes with alloy composition [6], but the modulated phases (commonly labelled 5M and 7M) [7, 8] displaying magnetic shape memory only exist if the MT transition temperature T MT is lower than the Curie temperature T C [6, 9]. In these structures the minimum in free energy is shifted such that the lattice constant ratio is c/a < 1 in the splitting (tetragonal or orthorhombic) of the high temperature cubic austenite (AUS) phase, compared to the usual global minimum found at c/a > 1 in the non-modulated tetragonal phase. Theoretical studies suggest that the modulation of the structure stabilizes this new minimum [10][11][12]. In Ni 2 MnGa compounds, we then have a situation where the interplay between an incommensurate structural modulation, a splitting of the electronic states due to the tetragonal or orthorhombic distortion of the cubic lattice and the ferromagnetic order combine to stabilize a phase displaying a large magnetic shape memory effect.In this letter we study this interplay by employing ultrafast time resolved x-ray and optical methods to separate the three types of order in time and to investigate the possible coupling between ferromagnetism and the modulated str...

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Influence of structural transition on transport and optical properties of Ni2MnGa alloy

Cited by 28 publications

References 19 publications

Properties of Magnetic Shape Memory Alloys in Martensitic Phase

Properties of Magnetic Shape Memory Alloys in Martensitic Phase

Intermartensitic phase transformations in Ni–Mn–Ga studied under magnetic field

Structural and magnetic dynamics in the magnetic shape-memory alloyNi2MnGa

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