Structural and Magnetic Studies on Ni-Mn-Ga-based Ferromagnetic Shape Memory Alloys.

Authors :: Mathur, R. P.
Singh, R. K.
Ray, S.
Manivel Raja, M.
Ghosal, P.
Chandrasekaran, V.
Source :: Defence Science Journal; 2011, Vol. 61 Issue 3, p275-284, 10p
Publication Year :: 2011
Abstract: Quaternary Ni<subscript>50</subscript> Fe<subscript>x</subscript> Mn<subscript>30-x</subscript> Ga<subscript>20</subscript> (x = 2.5, 5, and 15) and Ni<subscript>45</subscript> Fe<subscript>5</subscript> Mn<subscript>30</subscript> Ga<subscript>20</subscript> alloys based on modification of ferromagnetic shape memory alloy ternary Ni<subscript>50</subscript> Mn<subscript>30</subscript> Ga<subscript>20</subscript> composition prepared by vacuum arc melting and subsequent heat-treatment were investigated to understand the effect of varying Fe-content in Ni-Fe-Mn-Ga alloys. With increasing Fe-content, saturation magnetisation and Curie temperature increased, however martensite transformation temperature did not show a systematic variation. The <superscript>57</superscript>Fe Mossbauer spectra showed three distinct sub-spectra depending upon the site occupancy by Fe-atoms. The results are explained with site selection by Fe-atom in parent L2<subscript>1</subscript> lattice. [ABSTRACT FROM AUTHOR]

Subjects :: SHAPE memory alloys
FERROMAGNETIC materials
VACUUM arcs
MARTENSITE
MAGNETIZATION
THERMOMAGNETISM

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