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Title: Effect of niobium addition on the martensitic transformation and magnetocaloric effect in low hysteresis NiCoMnSn magnetic shape memory alloys

The effect of Nb substitution for Ni in Ni{sub 45}Co{sub 5}Mn{sub 40}Sn{sub 10} magnetic shape memory alloys on their magnetic properties, martensitic transformation characteristics, transformation hysteresis, and magnetocaloric properties was studied using wavelength-dispersive X-ray spectroscopy, differential scanning calorimetry, and the temperature and field dependence of the magnetization. Ni{sub 45}Co{sub 5}Mn{sub 40}Sn{sub 10} alloy has a very low transformation hysteresis; however, the martensitic transformation temperatures are notably above room temperature, which is not desirable for magnetic refrigeration applications. In this study, small quantities of Nb substitution were shown to drastically shift the transformation temperatures to lower temperatures, at a rate of 68‚ÄČK/at. % Nb, which is needed for household refrigeration. The austenite Curie temperature also decreased with increasing Nb content. However, a decrease in the latent heat of the martensitic transition was observed, which negatively affects the magnetic field-induced adiabatic temperature change capability. Still, the relatively large transformation entropy and the low transformation hysteresis make the Nb-doped Ni{sub 45}Co{sub 5}Mn{sub 40}Sn{sub 10} alloys potential candidates for solid state refrigeration near room temperature.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [4]
  1. Department of Engineering Physics, Ankara University, 06100 Ankara (Turkey)
  2. Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843 (United States)
  3. Department of Physics, Ondokuz Mayis University, 55139 Samsun (Turkey)
  4. (United States)
Publication Date:
OSTI Identifier:
22395466
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AUSTENITE; CALORIMETRY; COBALT ALLOYS; CURIE POINT; DIFFERENTIAL THERMAL ANALYSIS; DOPED MATERIALS; ENTROPY; HYSTERESIS; MAGNETIC FIELDS; MAGNETIC PROPERTIES; MAGNETIZATION; MANGANESE BASE ALLOYS; NICKEL BASE ALLOYS; NIOBIUM ADDITIONS; PHASE TRANSFORMATIONS; REFRIGERATION; SHAPE MEMORY EFFECT; TEMPERATURE RANGE 0273-0400 K; X-RAY SPECTROSCOPY