Large Inverse Magnetic Entropy Changes and Magnetoresistance in the Vicinity of a Field-Induced Martensitic Transformation in Ni50−xCoxMn32−yFeyGa18

Authors

Arjun K. Pathak, Southern Illinois University Carbondale
Igor Dubenko, Southern Illinois University Carbondale
Haluk E. Karaca, University of Kentucky
Shane Stadler, Louisiana State University
Naushad Ali, Southern Illinois University Carbondale

Comments

© 2010 American Institute of Physics

Published in Applied Physics Letters, Vol. 97 No. 6 (2010) at doi: 10.1063/1.3467460

Abstract

Significantly large inverse magnetic entropy changes (ΔS_M) and magnetoresistance (MR) were observed at the inverse martensitic phase transitions of the Ga-based magnetic shape memory Heusler alloys: Ni_50−xCo_xMn_32−yFe_yGa₁₈. The crystal structures of alloys were tetragonal at 300 K and the phase transition temperatures and magnetic properties were found to be correlated with the degree of tetragonal distortion. The maximum peak values of the ΔS_M and MR at H = 5 T were determined as ≈ (+)31 J Kg⁻¹ K⁻¹ and ≈−21%, respectively, for x = 8 and y = 2. The relatively small hysteretic loss and large refrigeration capacity observed in this system make these compounds promising materials for applications.

Recommended Citation

Pathak, Arjun K., Dubenko, Igor, Karaca, Haluk E., Stadler, Shane and Ali, Naushad. "Large Inverse Magnetic Entropy Changes and Magnetoresistance in the Vicinity of a Field-Induced Martensitic Transformation in Ni50−xCoxMn32−yFeyGa18." (Aug 2010).