Microstructure, magnetic properties and magnetocaloric effect in melt-spun Ni–Mn–Ga ribbons

• Published in: Journal of alloys and compounds 2009-06, Vol.478 (1), p.59-62
• Main Authors: Rao, N.V. Rama, Gopalan, R., Chandrasekaran, V., Suresh, K.G.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic measurements; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric; Magnetocaloric effect, magnetic cooling; Martensitic transformations; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Rapid solidification
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.12.015

Structural transformation, microstructure and magnetocaloric effect (MCE) were investigated in melt-spun Ni 55Mn 20.6Ga 24.4 and Ni 55Mn 19.6Ga 25.4 ribbons. Magnetic and thermal studies of the ribbons revealed the occurrence of simultaneous structural and magnetic transitions near room temperature with a narrow thermal hysteresis of magnetization ≈2 K. Maximum entropy changes (Δ S M) of −9.5 and −10.4 J/kg K have been obtained at 309 K for a field change of 2 T in Ni 55Mn 20.6Ga 24.4 and Ni 55Mn 19.6Ga 25.4 ribbons, respectively. The Ni 55Mn 19.6Ga 25.4 ribbon exhibits refrigeration capacity (RC) of 47 J/kg with low average hysteresis loss (≈1.5 J/kg) at the merged structural and magnetic transition temperature.