Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1798787 | Journal of Magnetism and Magnetic Materials | 2016 | 5 Pages |
Abstract
The present investigation addresses the magnetocaloric behaviour in a series of Ni77âxMnxGa23 (x=23, 24, 25, 27 and 29) rapidly solidified alloys prepared in the form of ribbons by melt spinning technique. The approach of the study is to identify the off-stoichiometric composition wherein room temperature magneto-structural transformation is achieved. The alloy chemistry was tailored through Mn incorporation for Ni such that the magnetic and structural transitions were at close proximity to achieve highest entropy value of ÎS equal to 8.51Â JÂ Kgâ1Â Kâ1 for #Mn24 ribbon measured at an applied field of 3Â T. When such transitions are more staggered as in #Mn29 the entropy value of ribbon reduced to as low as 1.61Â JÂ Kgâ1Â Kâ1. Near room temperature transformations in #Mn24 ribbon have been observed through calorimetric and thermomagnetic evaluation. Reverse martensitic transformation (martensiteâautstenite) temperature indicates not only distinct change in the saturation flux density but also an inter-martensitic phase. Microstructural analysis of #Mn24 alloy ribbon revealed structural ordering with the existence of plate morphology evidenced for martensitic phase.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Sushmita Dey, Satnam Singh, R.K. Roy, M. Ghosh, A. Mitra, A.K. Panda,