Influence of solidification microstructure on the magnetic properties of Ni-Mn-Sn Heusler alloys

TitleInfluence of solidification microstructure on the magnetic properties of Ni-Mn-Sn Heusler alloys
Publication TypeJournal Article
Year of Publication2008
AuthorsSchlagel DL, McCallum RW, Lograsso TA
Journal TitleJournal of Alloys and Compounds
Volume463
Pages38-46
Date PublishedSep
Type of ArticleArticle
ISBN Number0925-8388
Accession NumberISI:000258697300011
Keywordsalloy, field-induced strain, GA, Heusler alloy, magnetostriction, magnetostructural transformation, MARTENSITIC-TRANSFORMATION, Ni-Mn-Sn, phase, shape memory, shape-memory alloys, single-crystals
Abstract

There have been many investigations to identify new alloys exhibiting large magnetic field-induced strain and more recently, the giant magnetocaloric effect. For any particular alloy system, it is necessary to adjust composition to alter the magnetic ordering and structural transformation temperatures to achieve the desired field-induced response. For the Ni-Mn-Sn alloy system, this compositional tuning has dramatic effects on microstructural development significantly affecting both transitions. Solidification induced chemical variations, when not fully equilibrated, have been found to mask the intrinsic magonetostructural behavior in Ni50Mn37Sn13. The use of a phase purity criterion was found to be an insufficient descriptor for determining homogeneity. When both structural and chemical homogenization are achieved, the nature and sequence of the transitions were found to be: (1) austenite paramagnetic to ferromagnetic transition, (2) Coupled ferromagnetic austenite to paramagnetic martensite magnetostructural transition, and (3) paramagnetic to ferromagnetic martensite transition with Curie-Weiss behavior on heating above its Curie temperature. Published by Elsevier B.V.

DOI10.1016/j.jallcom.2007.09.049
Alternate JournalJ. Alloy. Compd.