Martensitic and magnetic domain structures of ferroics of the Ni-Mn-Ga and Co-Ni-Ga families

Breczko, Teodor; Гречишкин, Р. М.; Ilyashenko, S. E.; Nelaev, V. V.; Dovzhik, Krishna N.; Korpusov, O. M.

doi:10.1134/s1063783410010178

Cited by 5 publications

(1 citation statement)

References 6 publications

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“…Light microscopy is still the most frequently used technique that allows many phenomena occurring in shape memory alloys to be described [25]. Observations of the Co 48 Ni 22 Ga 30 single crystal using polarized light microscopy, called Kerr microscopy, showed that in a martensitic state each martensitic plane is divided into 180 • magnetic domains and the twin boundaries are 90 • magnetic domain walls of the Bloch type [26]. The 180 • magnetic domains are continuous within the crystal grains and intersect the planar mutually parallel walls of the martensitic domains.…”

Section: Introductionmentioning

confidence: 99%

Microstructural and In Situ Lorentz TEM Domain Characterization of As-Quenched and γ’-Precipitated Co49Ni30Ga21 Monocrystal

Żak

Dudziński

2020

Crystals

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The article concerns the rarely described magnetic domain structure of Heusler alloys in the case of a single crystal [100]-oriented Co-Ni-Ga alloy. The structure of the magnetic domains of the alloy was compared in two states: in the quenched and additionally aged state. Ageing led to precipitation of the spherical phase γ' nanoparticles (Co-rich, FCC lattice with a = 0.359 nm). Lorentz transmission electron microscopy observation methods combined with cooling and in situ heating of the sample in the transmission electron microscope in the temperature range from 140 K to 300 K were combined to observe the magnetic domain structure. Significant differences in the dimensions and morphology of magnetic domain boundaries have been demonstrated. The quenched sample showed no change in stripe domain structure when the aged sample showed significant development of branching magnetic structures. This may be due to a change in the chemical composition of the matrix resulting from a decrease in cobalt and nickel content at the expense of precipitations.

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Section: Introductionmentioning

confidence: 99%

Microstructural and In Situ Lorentz TEM Domain Characterization of As-Quenched and γ’-Precipitated Co49Ni30Ga21 Monocrystal

Żak

Dudziński

2020

Crystals

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Magnetic Domains and Twin Boundary Movement of NiMnGa Magnetic Shape Memory Crystals

et al. 2012

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Time‐resolved metallographic optical microscopy techniques are used together with magnetic domain imaging to clarify the interaction between magnetic domains and twin boundary (TB) motion in magnetic shape memory NiMnGa single crystals. The magnetic field and stress induced magnetic domain formation is imaged by a magneto‐optical indicator film technique. Reversible TB motion is visualized up to high actuation speeds. From domain observation at adjacent crystal surfaces the fundamental volume magnetic processes during strain and field induced TB motions are derived. For magnetic field induced structural reorientations a concurrent absence of magnetic domain wall motion is found. In contrast, for strain induced reorientations processes, a complete rearrangement of the magnetic domain structure by the moving TB is observed. Dynamic actuation experiments on TB motion reveal non‐linear time effects on TB mobility. In addition to training effects, the maximum field induced strain increases with actuation speed. Both effects can be interpreted as the interaction of moving twin boundaries with local non‐fixed defects. The summarized results provide key information for the understanding of the connection of magnetic and crystallographic domains in magnetic shape memory alloys and for the optimization of devices for future technical applications.

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Effect of external influences on the domain structure of soft ferroelectric ceramics

et al. 2016

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Martensitic and magnetic domain structures of ferroics of the Ni-Mn-Ga and Co-Ni-Ga families

Cited by 5 publications

References 6 publications

Microstructural and In Situ Lorentz TEM Domain Characterization of As-Quenched and γ’-Precipitated Co49Ni30Ga21 Monocrystal

Microstructural and In Situ Lorentz TEM Domain Characterization of As-Quenched and γ’-Precipitated Co49Ni30Ga21 Monocrystal

Magnetic Domains and Twin Boundary Movement of NiMnGa Magnetic Shape Memory Crystals

Effect of external influences on the domain structure of soft ferroelectric ceramics

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