Magnetic and magnetocaloric properties of Co2-xFexVGa Heusler alloys

Authors

K. Schroeder, South Dakota State University
J. Waybright, South Dakota State University
P. Kharel, University of Nebraska - Lincoln
W. Zhang, University of Nebraska - Lincoln
Shah R. Valloppilly, University of Nebraska-LincolnFollow
J. Herran, University of Northern Iowa
P. Lukashev, University of Northern Iowa
Y. Huh, South Dakota State University
R. Skomski, University of Nebraska-LincolnFollow
D. J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2018

Citation

AIP ADVANCES 8, 056431 (2018).

Comments

© 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.

Abstract

The magnetic and magnetocaloric properties of iron-substituted Co₂VGa alloys, Co_2-xFe_xVGa (x = 0, 0.1, 0.15, 0.2, 0.3), were investigated. The Fe-substituted samples, prepared by arc melting, melt spinning, and annealing, crystallized in the L2₁ Heusler structure, without any secondary phases. The Curie temperature and highfield magnetization at 50 K decreased from 345 K and 44 emu/g (1.90 μ_B/f.u.) for Co₂VGa to 275 K and 39 emu/g (1.66 μ_B/f.u.) for Co_1.7Fe_0.3VGa, respectively, but the maximum entropy change remained almost insensitive to Fe concentration for x ≤ 0.2, the highest value being 3.3 J/kgK at 7 T for Co_1.85Fe_0.15VGa. First-principle calculations show that Co2VGa retains its half-metallic band structure until at least 30% of the cobalt atoms are replaced by Fe atoms. The wide operating temperature window near room temperature and the lack of thermal and magnetic hysteresis are the interesting features of these materials for application in room-temperature magnetic refrigeration.