Influence of nano-VC on the structural and magnetic properties of MnAlC-alloy

Vitalii Shtender; Henry Stopfel; Daniel Hedlund; Dennis Karlsson; Rajasekhar Pothala; Björn Skårman; Fredrik Olsson; Hilmar Vidarsson; Gabriella Andersson; Peter Svedlindh; Martin Sahlberg

doi:10.1038/s41598-021-93395-2

Influence of nano-VC on the structural and magnetic properties of MnAlC-alloy

Sci Rep. 2021 Jul 14;11(1):14453. doi: 10.1038/s41598-021-93395-2.

Authors

Affiliations

¹ Ångström Laboratory, Department of Chemistry, Uppsala University, Box 538, 751 21, Uppsala, Sweden. vitalii.shtender@kemi.uu.se.
² Department of Materials Science and Engineering, Uppsala University, Box 35, 751 03, Uppsala, Sweden.
³ Department of Physics and Astronomy, Uppsala University, Box 516, 751 20, Uppsala, Sweden.
⁴ Ångström Laboratory, Department of Chemistry, Uppsala University, Box 538, 751 21, Uppsala, Sweden.
⁵ Höganäs AB, Bruksgatan 35, 263 83, Höganäs, Sweden.

Abstract

Alloys of Mn₅₅Al₄₅C₂ with additions of VC nano-particles have been synthesized and their properties evaluated. The Mn₅₅Al₄₅C₂(VC)_x (x = 0.25, 0.5 and 1) alloys have been prepared by induction melting resulting in a high content of the ferromagnetic τ-phase (> 94 wt.%). Powder X-ray diffraction indicates that nano-VC can be dissolved in the alloy matrix up to 1 at.%. On the other side, metallography investigations by scanning electron microscopy and scanning transmission electron microscope show inclusions of the nanosized additives in the microstructure. The effect of nano-VC on the grain and twin boundaries has been studied by electron backscattering diffraction. The magnetization has been measured by magnetometry up to 9 T while the domain structure has been studied using both magnetic force microscopy as well as Kerr-microscopy. For nano-VC contents above 0.25 at.%, a clear increase of the coercive force is observed, from 57 to 71 kA/m. The optimum appears to be for 0.5 at.% nano-VC which shows a 25% increase in coercive force without losing any saturation magnetization. This independent increase in coercivity is believed to originate from the nano-VC reducing the overall magnetic domain size. Overall, we observe that addition of nano-VC could be an interesting route to increase the coercive force of MnAl, without sacrificing saturation magnetization.