Magnetocaloric Effect in Quintenary and Sextenary Heusler Alloys

ORAL

Abstract

Measurements on alloys based on the shape-memory compound Ni2MnGa have revealed large entropy changes, ΔS, in magnetic fields, H. Significant magnetocaloric effects are generally observed in materials containing expensive rare-earth elements like Gd or toxic elements like As. Such materials are ill-suited for commercial magnetic refrigeration applications. In contrast, alloys based on Ni2MnGa contain relatively inexpensive and non-toxic elements; a large magnetocaloric effect in such materials would be of particular interest. In this talk, we present heat capacity and magnetization measurements on polycrystalline samples of several quintenary and sextenary Heusler alloys. We determined ΔS using heat capacity measurements performed in applied magnetic fields. Isothermal magnetization measurements as a function of H were performed on selected samples at temperatures in the vicinity of the magnetic phase transition. Using a combination of magnetization and heat capacity data, we estimated the adiabatic temperature change, ΔTa, that results from applying a magnetic field of H = 5 T. The largest value we observed was ΔTa ~ 3.5 K, but further work may reveal larger effects as chemical compositions are optimized.

–

Presenters

  • Benjamin White

    Department of Physics, Central Washington University, Department of Physics, Central Washington Univ

Authors

  • Benjamin White

    Department of Physics, Central Washington University, Department of Physics, Central Washington Univ

  • R. Barabash

    Oak Ridge National Laboratory

  • O. Barabash

    The University of Tennessee

  • Inho Jeon

    University of California, San Diego, Physics, University of California, San Diego, Department of Physics, University of California, San Diego, Materials Science and Engineering, University of California, San Diego, Materials Science and Engineering Program and Center for Advanced Nanoscience, University of California, San Diego, Materials Science and Engineering Program, and Center for Advanced Nanoscience, Univ of California - San Diego, Materials Science and Engineering Program, Univ of California - San Diego, University of California-San Diego

  • M Brian Maple

    Department of Physics, University of California, San Diego, University of California, San Diego, Physics, University of California, San Diego, Univ of California - San Diego, Department of Physics and Center for Advanced Nanoscience, University of California, San Diego, Department of Physics, Center for Advanced Nanoscience,Materials Science and Engineering Program , Univ of California - San Diego, Department of Physics, University of California San Diego, Physics, Univ of California - San Diego, University of California-San Diego, UC San Diego, Physics, UC San Diego