Title :
Magnetocaloric Effect in Ni–Mn–Ga Alloys
Author :
Mandal, K. ; Pal, D. ; Scheerbaum, N. ; Lyubina, J. ; Gutfleisch, O.
Author_Institution :
S. N. Bose Nat. Center for Basic Sci., Kolkata
Abstract :
Heusler alloys with nickel rich nominal composition Ni2+xMn1-xGa (x = 0.16 - 0.26) were prepared by arc-melting and subsequent homogenization by annealing. A large magnetic entropy change around room temperature was observed in the alloy where martensite-austenite structural and ferro-para magnetic transition temperatures almost coincide with each other. It also shows large hysteresis in the magnetization isothermals. A sharp peak in the specific heat versus temperature curve indicates a first-order transition at the temperature of large entropy change.
Keywords :
entropy; ferromagnetic materials; ferromagnetic-paramagnetic transitions; gallium alloys; magnetisation; magnetocaloric effects; manganese alloys; nickel alloys; paramagnetic materials; reverse martensitic transformations; specific heat; Heusler alloys; Ni-Mn-Ga alloys; NiMnGa; ferro-para magnetic transition; first-order transition; magnetic entropy; magnetization isothermals; magnetocaloric effect; martensite-austenite structural transition; specific heat; Austenite phase; Heusler alloys; magnetocaloric effect; martensite phase;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2008.2002481
