Deviation of bulk magnetic property changes from martensitic transition temperature in Ni-Mn-Sn heusler alloys at low fields Conference Paper uri icon

abstract

  • We describe the anomalous magnetic field dependence of the magnetization change associated with the austenite to martensite magneto-structural transition in the Ni-Mn-Sn Heusler alloy system. At small external magnetic fields (< 0.1 T), the critical temperatures of the phase transition measured by magnetization are 5 C lower than those measured by electrical resistivity or predicted by thermodynamic theory. This leads to a depression of the temperature of the maximum magnetic entropy change (one measure of the magnetocaloric effect) relative to that of the phase transition in small fields. The observed anomaly is most likely attributable to a coupling between phase boundaries and either twin interfaces or magnetic domain structures in the two-phase alloy. This coupling causes magnetization of the two-phase alloy to no longer be proportional to the mass fractions of austenite and martensite present in the sample, as it is at higher fields.

published proceedings

  • Materials Science and Technology Conference and Exhibition 2009, MS and T'09

author list (cited authors)

  • Shamberger, P., Pakhomov, A., & Ohuchi, F.

publication date

  • January 1, 2009 11:11 AM