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Title: Calorimetric and magnetic study for Ni{sub 50}Mn{sub 36}In{sub 14} and relative cooling power in paramagnetic inverse magnetocaloric systems

The non-stoichiometric Heusler alloy Ni{sub 50}Mn{sub 36}In{sub 14} undergoes a martensitic phase transformation in the vicinity of 345‚ÄČK, with the high temperature austenite phase exhibiting paramagnetic rather than ferromagnetic behavior, as shown in similar alloys with lower-temperature transformations. Suitably prepared samples are shown to exhibit a sharp transformation, a relatively small thermal hysteresis, and a large field-induced entropy change. We analyzed the magnetocaloric behavior both through magnetization and direct field-dependent calorimetry measurements. For measurements passing through the first-order transformation, an improved method for heat-pulse relaxation calorimetry was designed. The results provide a firm basis for the analytic evaluation of field-induced entropy changes in related materials. An analysis of the relative cooling power (RCP), based on the integrated field-induced entropy change and magnetizing behavior of the Mn spin system with ferromagnetic correlations, shows that a significant RCP may be obtained in these materials by tuning the magnetic and structural transformation temperatures through minor compositional changes or local order changes.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ; ;  [4] ;  [1] ;  [3]
  1. Department of Physics and Astronomy, Texas A and M University, College Station, Texas 77843 (United States)
  2. Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843 (United States)
  3. (United States)
  4. School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China)
Publication Date:
OSTI Identifier:
22402693
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AUSTENITE; CALORIMETRY; COOLING; ENTROPY; HEAT; HEUSLER ALLOYS; HYSTERESIS; MAGNETIZATION; MARTENSITIC STEELS; PARAMAGNETISM; PULSES