Cylindrical nanowires made of Co2FeSn Heusler alloy with high spin polarization have been synthetized via template-assisted electrochemical deposition in nanoporous anodic alumina membranes. Their microstructure and morphology have been characterized by in situ studies of X-ray diffraction, together with scanning and transmission electron microscopy techniques. The basic structural and magnetic characterization revealed a B2-type cubic ordered Heusler structure with a lattice parameter of around 5.8 Å and the [110] direction, preferably aligned with the longitudinal axis of the polycrystalline nanowires. The easy magnetization axis is parallel to the nanowire’s axis too. The point-contact Andreev reflection spectroscopic measurements performed on the nanowire’s fresh surface released high polarization values, that is, P = 0.85–1, and prove that the high spin polarization or half-metallicity will be preserved in the nanoscale regime. The presented results open the possibilities toward future exploration of Heusler nanowires with high spin polarization, which are promising materials for applications in spintronics and high-density magnetic data recording.

Cylindrical Co2FeIn Heusler alloy nanowires are synthesized via template-assisted electrochemical deposition into the hexagonally self-ordered nanopores of hard-anodic alumina membranes. The electroplated nanowires, with 180 ±20 nm in diameter and around 14.5 µm in length, exhibit a polycrystalline nature and they are homogenous in composition. High-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) and Xray diffraction (XRD) analysis confirmed a cubic A2 disordered phase of the ferromagnetic Heusler compound, with a lattice parameter of a = 5.764 ± 0.001 Å. In addition, these structural characterizations reveal that the Co2FeIn nanowires display a polycrystalline structure with a pronounced {220} texture. The temperature dependent magnetization behavior and anisotropy field distribution calculations display a dominant role of shape, magnetocrystalline and magnetoelastic terms on the effective magnetic anisotropy of Co2FeIn alloyed nanowire arrays. Magneto-optical Kerr effect measurements performed on single freestanding nanowires, after releasing from the hosting alumina templates, confirmed competing behavior between shape and magnetocrystalline anisotropy contributions, which lead to complex magnetization reversal process. This fabrication technique offers a promising and new forward-looking synthesis of novel Heusler nanomaterials for spintronics applications.

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Large scale production of single crystalline phase of Heusler Co 2 FeSi alloy microwire is reported. The long microwire (~ 1 km) with the metallic nucleus diameter of about 2 µm is characterized by well oriented monocrystalline structure (B2 phase, with the lattice parameter a = 5.615 Å). Moreover, the crystallographic direction [101] is parallel to the wire´s axis along the entire length. Additionally, the wire is characterized by exhibiting a high Curie temperature (Tc > 800 K) and well-defined magnetic anisotropy mainly governed by shape. Electrical resistivity measurement reveals the exponential suppression of the electron-magnon scattering which provides strong evidence on the half-metallic behaviour of this material in the low temperature range.

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