“…1 ). This morphology is similar to the one observed in 19 . Magnetic susceptibility and ferromagnetic resonance (FMR) measurements showed that the film exhibits a ferromagnetic ordering with the Curie temperature around 370 K. Figure 1 XRD pattern for Ni-Mn-Ga/MgO(001) thin film at room temperature showing (020) and (040) peaks of the orthorhombic unit cell for the film and the reflections belonging to the substrate.…”
Section: Resultssupporting
confidence: 88%
“…A 300 nm-thick Ni 52.3 Mn 26.8 Ga 20.9 (at.%) film was epitaxially grown by magnetron sputtering onto a MgO(001) substrate. The composition of the film and sample preparation procedure was the same as for the samples investigated in 19 . The composition and the preparation procedure were chosen to obtain epitaxial films with the martensitic transformation temperature well above the Curie temperature to get rid of any influence of the transformation effects on magnetoresistance.…”
Section: Resultsmentioning
confidence: 99%
“…Previously we discussed this issue in ref. 19 for similar epitaxial NiMnGa film with a thickness of 500 nm. It has been shown there that the twin width l is comparable with the exchange correlation length (domain wall width), , where a is the lattice parameter, H E and H A are the internal magnetic fields that characterize the spin exchange interaction and the magnetocrystalline anisotropy, respectively.…”
Section: Discussionmentioning
confidence: 99%
“…The rough estimation of the exchange correlation length (7–19 nm) was performed for single variant martensite using the existed experimental data and theoretical calculations. Although the mentioned theory can’t be directly applied to calculate δ for exchange coupled twins it is safe to state that this value should be higher due to the effective anisotropy field reduction 19 , up to 30 nm. Therefore the exchange correlation length in our 300 nm film is also comparable with the twin width ( l ≈ 60 nm).…”
Magnetic shape memory alloys are under intensive investigation due to their unusual physical properties, such as magnetic shape memory effect, magnetic field induced superelasticity, direct and inverse magnetocaloric effect etc., promising for novel applications. One of the intriguing properties of these materials in a single phase state is a giant magnetoresistance. Here we report the remarkable results about the magnetoresistive properties of epitaxial films of Ni52.3Mn26.8Ga20.9 magnetic shape memory alloy in the temperature range of 100–370 K, well below the martensitic transformation temperature. It was found that the formation of non-collinear magnetic structure due to a nanotwinning of the film results in electron scattering on such a structure and noticeable negative magnetoresistance in the entire investigated temperature range.
“…1 ). This morphology is similar to the one observed in 19 . Magnetic susceptibility and ferromagnetic resonance (FMR) measurements showed that the film exhibits a ferromagnetic ordering with the Curie temperature around 370 K. Figure 1 XRD pattern for Ni-Mn-Ga/MgO(001) thin film at room temperature showing (020) and (040) peaks of the orthorhombic unit cell for the film and the reflections belonging to the substrate.…”
Section: Resultssupporting
confidence: 88%
“…A 300 nm-thick Ni 52.3 Mn 26.8 Ga 20.9 (at.%) film was epitaxially grown by magnetron sputtering onto a MgO(001) substrate. The composition of the film and sample preparation procedure was the same as for the samples investigated in 19 . The composition and the preparation procedure were chosen to obtain epitaxial films with the martensitic transformation temperature well above the Curie temperature to get rid of any influence of the transformation effects on magnetoresistance.…”
Section: Resultsmentioning
confidence: 99%
“…Previously we discussed this issue in ref. 19 for similar epitaxial NiMnGa film with a thickness of 500 nm. It has been shown there that the twin width l is comparable with the exchange correlation length (domain wall width), , where a is the lattice parameter, H E and H A are the internal magnetic fields that characterize the spin exchange interaction and the magnetocrystalline anisotropy, respectively.…”
Section: Discussionmentioning
confidence: 99%
“…The rough estimation of the exchange correlation length (7–19 nm) was performed for single variant martensite using the existed experimental data and theoretical calculations. Although the mentioned theory can’t be directly applied to calculate δ for exchange coupled twins it is safe to state that this value should be higher due to the effective anisotropy field reduction 19 , up to 30 nm. Therefore the exchange correlation length in our 300 nm film is also comparable with the twin width ( l ≈ 60 nm).…”
Magnetic shape memory alloys are under intensive investigation due to their unusual physical properties, such as magnetic shape memory effect, magnetic field induced superelasticity, direct and inverse magnetocaloric effect etc., promising for novel applications. One of the intriguing properties of these materials in a single phase state is a giant magnetoresistance. Here we report the remarkable results about the magnetoresistive properties of epitaxial films of Ni52.3Mn26.8Ga20.9 magnetic shape memory alloy in the temperature range of 100–370 K, well below the martensitic transformation temperature. It was found that the formation of non-collinear magnetic structure due to a nanotwinning of the film results in electron scattering on such a structure and noticeable negative magnetoresistance in the entire investigated temperature range.
“…A: Magnetic field influence on martensite transformation in ferromagnetic shape memory alloys and metamagnetic shape memory alloys [64][65][66][67][68][69][70]; B: Magnetic anisotropy of the ferromagnetic shape memory alloys [71,72]; C: Magnetostriction [73,74].…”
Section: Magnetic Field-induced Strain and Magnetostriction In Shape mentioning
Abstract:The purpose of this review was to investigate the correlation between magnetism and crystallographic structures as it relates to the martensite transformation of Ni 2 MnGa type alloys, which undergo martensite transformation below the Curie temperature. In particular, this paper focused on the physical properties in magnetic fields. Recent researches show that the martensite starting temperature (martensite transformation temperature) T M and the martensite to austenite transformation temperature (reverse martensite temperature) T R of Fe, Cu, or Co-doped Ni-Mn-Ga ferromagnetic shape memory alloys increase when compared to Ni 2 MnGa. These alloys show large field dependence of the martensite transformation temperature. The field dependence of the martensite transformation temperature, dT M /dB, is −4.2 K/T in Ni 41 Co 9 Mn 32 Ga 18 . The results of linear thermal strain and magnetization indicate that a magneto-structural transition occurred at T M and magnetic field influences the magnetism and also the crystal structures. Magnetocrystalline anisotropy was also determined and compared with other components of Ni 2 MnGa type shape memory alloys. In the last section, magnetic field-induced strain and magnetostriction was determined with some novel alloys.
OPEN ACCESS
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
