2015/06/30 by Sudip Kumar Sarkar, Sarita Sarita, Sarita +6
Chemistry · Materials Science · Physics and Astronomy · #Alloy #Analytical Chemistry (journal) #Austenite #Chemistry #Condensed matter physics #Curie temperature #Differential scanning calorimetry #Diffusionless transformation #Ferromagnetism #Magnetic and transport properties of perovskites and related materials #Magnetic domain #Magnetic field #Magnetic refrigeration #Magnetic shape-memory alloy #Magnetization #Martensite #Materials science #Metallurgy #Microstructure #Multiferroics and related materials #Shape Memory Alloy Transformations #Shape-memory alloy #Thermodynamics #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.jallcom.2016.02.039
published as Journal of Alloys and Compounds Volume 670, Pages 281--288, 15 June 2016 · 32 pages, 10 figures, 4 tables, submitted to Journal of Alloys and Compounds
arxiv created 2015/07/23 · openalex publication_date 2016/02/09 · arxiv updated 2016/03/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In an effort to produce Giant Magnetocaloric effect (GMCE) near room temperature, in a first ever such study, the austenite transformation temperature (As) was fine tuned to ferromagnetic Curie temperature (TC) in Ferromagnetic Shape Memory Alloys (FSMA) and a large GMCE of delta-SM = - 81.75 J/Kg-K was achieved in Ni50Mn18.5Cu6.5Ga25 alloy during reverse martensitic transformation (heating cycle) for a magnetic field change of 9 T at 302.5 K. Fine tuning of As with TC was achieved by Cu substitution in Ni50Mn25-xCuxGa25 (0< x < 7.0)-based FSMAs. Characterizations of these alloys were carried out using Optical and Scanning Electron Microscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and DC magnetization measurements. Addition of Cu to stoichiometric Heusler type Ni2MnGa increases the martensitic transformation temperatures and decreases TC. Concurrently, DSM increases with Cu addition and peaks at 6.5 at. % Cu for which there is a virtual overlap between TC and As. Maximum Refrigerant Capacity (RCP) of 327.01 J/Kg was also achieved in the heating cycle for 9 T field change at 302.5 K. Corresponding values for the cooling cycle measurements (measured during forward transformation) were 30.4 J/Kg-K and 123.52 J/Kg respectively for the same 6.5 at. % Cu sample and same thermo-magnetic conditions.