Structural and magnetic characterisation of Co substituted Ni₂MnSb Heusler alloy: effect of cobalt substitution on magnetism and Curie temperature

ABSTRACT

In this study, Ni_2-xCo_xMnSb full-Heusler alloys (1.00 ≤ x ≤ 1.75) were prepared by arc melting process, and examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and SQUID. The L2₁ crystal structure of the synthesised Heusler alloy was confirmed by XRD patterns, and it was observed that the use of Co instead of Ni caused a decrease in the interatomic distance. The magnetisation results revealed that all samples show ferromagnetic (FM) behaviour, and substitution Co for Ni leads to increasing FM interactions in the samples. The calculated magnetic moment per formula unit increase from 4.38 µB(x = 1) to 5.17 µB (x = 1.75). On the other hand, the increase in FM interaction caused an increase in ferromagnetic-paramagnetic (PM) phase transition (T_C) temperatures from 513 (x = 1) to 568 K (x = 1.75). The ability to control the Curie temperature with Co substitution makes these alloys suitable candidates for future spintronics and magnetoelectronic applications.

KEYWORDS:

• Ni_2-xCo_xMnSb
• full-Heusler alloys
• cobalt doping
• Curie temperature
• ferromagnetic interaction

Acknowledgements

This work was supported by the Erciyes University Research Foundation [project numbers FBA-2016-6688 and FDK-2017-7359]. The authors would like to thank Sezen Aksoz from Physics Department at Nevşehir Hacı Bektaş Veli University, Ali Bayri and Serdar Altin from Physics Department at İnönü University for providing experimental support and their scientific contribution. Erdinc Oz would like to thank Ankara University Acceleration Technologies Institute for providing financial support from TARLA project [grant numbers 2006K-120470].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Erciyes University Research Foundation [project numbers FBA-2016-6688 and FDK-2017-7359]. Erdinc Oz would like to thank Ankara University Acceleration Technologies Institute for providing financial support from TARLA project [grant number 2006K-120470].