Temperature dependence of reversible field-induced strain and magnetization changes in Ni-Mn-Ga single crystals

Author

Heczko, O. ; Straka, L. ; Hannula, S.-P.

Author_Institution

Lab. of Phys. Metall. & Mater. Sci., Helsinki Univ. of Technol., Espoo, Finland

fYear

2005

fDate

4-8 April 2005

Firstpage

1937

Lastpage

1938

Abstract

The alloys close to stoichiometric Ni₂MnGa with Mn excess are prepared by a directional solidification method. Three single crystal alloys having 5M martensitic structure and exhibiting the magnetic shape memory effect (MSME) are studied at room temperature. The martensite-to-austenite transformation temperature varies from 314 K to 343 K. The MSME of the crystals or structural reorientation is then evaluated by simultaneous measurements of the magnetization and strain in slowly changing magnetic field at different temperatures and at a constant compressive stress. The magnetization changes observed during the MSME reflect the structural reorientation or martensitic variant redistribution of the crystals.

Keywords

directional solidification; gallium alloys; internal stresses; magnetisation; manganese alloys; martensitic structure; nickel alloys; reverse martensitic transformations; shape memory effects; stoichiometry; 293 to 298 K; 314 to 343 K; Ni₂MnGa; compressive stress; directional solidification method; magnetic shape memory effect; magnetization; martensite-to-austenite transformation; martensitic structure; room temperature; single crystal alloys; strain; structural reorientation; Crystals; Magnetic field induced strain; Magnetic field measurement; Magnetization; Manganese alloys; Nickel alloys; Shape memory alloys; Strain measurement; Stress measurement; Temperature dependence;

fLanguage

English

Publisher

ieee

Conference_Titel

Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International

Print_ISBN

0-7803-9009-1

Type

conf

DOI

10.1109/INTMAG.2005.1464405

Filename

1464405