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We have employed melt-spinning method to produce Ni 2 MnSn-based half-metallic Heusler alloy. It allows fast and simple production of large amount of materials in a single production step avoiding high temperature post-production annealing. Microstructural, magnetic and spin polarization study of Ni 2 MnSn ribbon is used for characterization. SEM analysis reveals the polycrystalline structure with the columnar crystals grown perpendicularly to the ribbon plane. A single-phase austenite with L2 1 structure was confirmed by X-ray. Magnetic measurements shows the ordinary ferromagnetic behavior with Curie temperature 344 K and magnetic moment 4.08 µ B /f.u. Particular crystal structure leads to the well defined anisotropy having an easy plane in the ribbon's plane. Finally, the spin polarization parameter P 0 estimated by Point-Contact Andreev-reflection Spectroscopy is varying in the range 40–70% for Ni 2 MnSn which is comparable with other values reported earlier for other Heusler alloys. [ABSTRACT FROM AUTHOR]

We present the study on production and structural, electric and magnetic properties of superconductive Ni2NbSn Heusler alloy. The sample has been produced by melt-spinning method using tangential speed of copper wheel 20 m/s. Polycrystalline structure has been obtained showing single phase with B2 disorder with lattice constant a = 6:1654 Å. Resistance measurement shows superconductive behavior with critical temperature close to 5 K. Magnetic measurements also exhibit diamagnetic contribution from superconductive phase. Additionally, the ferromagnetic state has been observed below 20 K, which points to the coexistence of magnetic and superconducting state. [ABSTRACT FROM AUTHOR]

We report on fabrication, structural and magnetic properties of novel Heusler-type glass coated Ni2FeSi microwires that were prepared by the Taylor-Ulitovsky method, having a metallic nucleus diameter about 3.9 μm and total sample diameter of 39 μm. This single step and low cost fabrication technique offers to prepare up to km of glass-coated microwires starting from few g of cheap elements for diverse applications. The X-ray diffraction data from the metallic nucleus indicates L21 crystalline structure (a = 5:563 Å), with a possible DO3 disorder. Magnetic measurements determined the Curie temperature well above the room temperature (770 K) together with uniform easy magnetization axis of the metallic core, which predisposes this material to a suitable candidate for spintronic applications. [ABSTRACT FROM AUTHOR]

• Production of Ni 54 Fe 19 Ga 23 X 4 glass-coated microwires doped by X = B, Al, Ga, In is presented. • The valence electron concentration (e/a) was kept constant. • The structural transition is very sensitive to chemical doping. • The fine-tuning of the composition may adjust the magnetocaloric properties. The influence of alloying in Ni 54 Fe 19 Ga 23 X 4 Heusler glass-coated microwires doped by X = B, Al, Ga, In is presented in this work. Even though the alloys exhibit different chemical compositions, the valence electron concentration (e/a) was constant. Furthermore, basic magnetic and resistivity measurements have been performed to determine the chemical doping effect on the magnetic properties and the associated structural transformation. Results point to the fact that the fine-tuning of the chemical composition may be a suitable tool for adjusting the Curie temperature, transformation temperature, and magnetocaloric properties of the glass-coated microwires. In the case of Ga and the Al -doped alloy, a thermal hysteresis can be distinguished in the M(T) dependences at saturation magnetic field, pointing to the presence of the structural transformation. Moreover, the 4% Al doping shifts the structural transformation temperature and the Curie temperature almost to the same position. On the other hand, B and In doping may lead to the disappearance or shift of the structural transformation out of the measurement range (100–400 K). Resistivity measurements proved these results. [ABSTRACT FROM AUTHOR]

Abstract The structural, magnetic and magnetocaloric properties of glass-coated magnetic microwires, composed of Ni 2 MnGa and produced with the Taylor-Ulitovski technique, have been investigated with XRD, EBSD, SEM and magnetization measurements. At room temperature, the microwires exhibit a monocrystalline phase with a Cu 2 MnAl-type crystal structure (space group Fm-3m; cell parameter a = 5.832 Å). The microwires in this study show a magnetocaloric effect with a sharp martensitic transformation in the range of 185–195 K, as well as a magnetocaloric effect owing to the magnetic phase transition at the Curie temperature. Due to the different strength of anisotropy and easy magnetization axis, the magnetocaloric effect during the martensitic transformation exhibit a maximum at low fields (0.5 T), and high efficiency (defined as a ratio between refrigerant capacity and applied magnetic field) at 0.2 T. Graphical abstract Image 1 Highlights • Large scale production of monocrystalline Heusler micro-wire is reported. • Such a wire is characterized by well oriented anisotropy. • Half-metallic behaviour is observed in the low temperature range. [ABSTRACT FROM AUTHOR]

Martensitic transformation (MT), structural and magnetic properties were investigated in a rapidly quenched Cu-doped Ni–Fe-Ga ribbon. The X-ray room temperature diffraction pattern showed the austenitic phase with the presence of the martensitic phase in the sample that was confirmed by SEM images. We have found that residual martensitic phase disappears at 320 K, while the MT and magnetic phase transition occurs above room temperature. Thermally stable two-step behavior of the MT, associated with the intermartensitic transition, has been shown. The MT affects static magnetic properties showing a small difference in magnetization values between curves measured during the heating and cooling. Results were discussed in the frame of the copper dopant and internal stresses, arising in the ribbon due to the fabrication features. [ABSTRACT FROM AUTHOR]