Controlling the microstructure and associated magnetic properties of Ni0.2Mn3.2Ga0.6 melt-spun ribbons by annealing

Authors

Mahmud Khan, Miami University - OxfordFollow
Ohud Alshammari, Miami University - Oxford
Balamurugan Balamurugan, University of Nebraska-LincolnFollow
Bhaskar Das, University of Nebraska - Lincoln
David J. Sellmyer, University of Nebraska - LincolnFollow
Ahmad Us Saleheen, Louisiana State University at Baton Rouge
Shane Stadler, Louisiana State University at Baton Rouge

Date of this Version

2017

Citation

AIP Advances 7, 056230 (2017)

Comments

© 2017 Author(s).

Open access

https://doi.org/10.1063/1.4977892

Abstract

Here we report on the structural and magnetic properties of Ni_0.2Mn_3.2Ga_0.6 melt- spun ribbons. The as-spun ribbons were found to exhibit mixed cubic phases that transform to non-cubic structure upon annealing. Additionally, an amorphous phase was found to co-exist in all ribbons. The SEM images show that minor grain forma- tion occurs on the as-spun ribbons. However, the formation of extensive nano-grains was observed on the surfaces of the annealed ribbons. While the as-spun ribbons exhibit predominantly paramagnetic behavior, the ribbons annealed under various thermal conditions were found to be ferromagnetic with a Curie temperature of about 380 K. The ribbons annealed at 450 ^◦C for 30 minutes exhibit a large coercive field of about 2500 Oe. The experimental results show that the microstructure and associated magnetic properties of the ribbons can be controlled by annealing techniques. The coercive fields and the shape of the magnetic hysteresis loops vary significantly with annealing conditions. Exchange bias effects have also been observed in the annealed ribbons.