Influence of the Geometrical Aspect Ratio on the Magneto-Structural Properties of Co2MnSi Microwires

Abstract

This present study illustrates the strong effect of geometrical parameters on the magneto-structural properties of Co2MnSi glass-coated microwires prepared using the Taylor–Ulitovsky method. Thus, there are three samples with different geometrical aspect ratios (ρ). The XRD analysis shows a significant change by modifying the aspect ratio; for ρ = 0.42, the main peak with miller indices (220) is recognized as an A2-type disordered cubic structure. For the sample with ρ = 0.46, mixed L21 and B2 cubic structures are observed. Meanwhile, in the sample with a low aspect ratio, ρ = 0.30, the perfect L21 ordered cubic structure is attained. Magnetic characterization has been carried out at a wide range of temperatures and magnetic fields. A significant increase in coercivity and normalized reduced remanence by decreasing the aspect ratio is detected. The change in the magnetic properties is attributed to the modification in the microstructure, which is induced during the fabrication process. Such a dependence on the microstructure and magnetic properties on the ρ-ratio can be associated either with the internal stress distribution and magnitude or with different quenching rates of microwires with different aspect ratios. The current findings demonstrate the tunability of the microstructure and magnetic properties of Co2MnSi-glass-coated microwires simply via a small modification in the geometric properties during the manufacturing process and without excreting any additional post-processing. The variation in the geometric parameters of Co2MnSi glass-coated microwires allows us to tune the magnetic properties and structure, which is essentially advantageous for sensing device development.

Crystal Structure and Properties of Heusler Alloys: A Comprehensive Review

“…The periodic table of each element that comprises the full-Heusler alloys is illustrated in Figure 1. Regularly, the first chemical element in the formula is the transition metal, whereas the main group atom is placed at the end, such as Co 2 MnGe and Co 2 MnSi [25,26]. Nonetheless, this rule does not apply to compounds like Li 2 CuSb, where one of the elements is defined as the most electropositive.…”

“…These deviations from stoichiometry can have significant impact on the alloy's physical, chemical and electrical properties. In such circumstances, the crystal's chemical order may shift from the totally ordered L2 1 structure to a partially ordered B2 within an exchange of atoms on the Y and Z sites positions or to a fully disordered A2 structure, where all the elements, X, Y and Z, are randomly distributed [25,26]. As a result, the distance between the magnetic atoms may also change, altering the exchange interaction between chemical elements [23].…”