Effects of Composition on the Properties of Magnetic Shape Memory Alloys

PDF

Authors
  1. Dunlap, R.A.
Corporate Authors
Weathervane Scientific Incorporated - Halifax, NS, Canada;Defence R&D Canada - Atlantic, Dartmouth NS (CAN)
Abstract
Magnetic shape memory alloys based on the Heusler alloy Ni2MnGa have been investigated experimentally and the magnetic interactions have been modeled on the basis of the indirect exchange coupling of localized magnetic moments. A variety of techniques including x-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, magnetization and Mössbauer effect spectroscopy have been utilized to measure the structural, thermal and magnetic properties of these alloys. Analysis of these results suggests that alloys containing a few at% Fe may be the most suitable for further exploration as commercially viable magnetic shape memory alloys. Theoretical investigations have shown that the indirect exchange coupling of magnetic moments associated with Mn ions on the Mn sites with other Mn-site Mn moments is ferromagnetic. This is also the case for Ni site moments associated with Ni ions. The coupling between Mn-site Mn moments and Mn ions located on Ni or Ga sites is antiferromagnetic. These observations explain the composition dependence of the saturation magnetization and the Curie temperature in off-stoichiometric Ni2MnGa alloys.

Il y a un résumé en français ici.

Report Number
DRDC-ATLANTIC-CR-2006-042 — Contractor Report
Date of publication
01 Mar 2007
Number of Pages
30
DSTKIM No
CA030401
CANDIS No
528934
Format(s):
CD ROM

Permanent link

Document 1 of 1

Date modified: