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Title: Optical and magneto-optical studies of martensitic transformation in Ni-Mn-Ga magnetic shape memory alloys

Optical and magneto-optical properties of single crystal of Ni{sub 50.1}Mn{sub 28.4}Ga{sub 21.5} magnetic shape memory alloy during its transformation from martensite to austenite phase were systematically studied. Crystal orientation was approximately along (100) planes of parent cubic austenite. X-ray reciprocal mapping confirmed modulated 10 M martensite phase. Temperature depended measurements of saturation magnetization revealed the martensitic transformation at 335 K during heating. Magneto-optical spectroscopy and spectroscopic ellipsometry were measured in the sample temperature range from 297 to 373 K and photon energy range from 1.2 to 6.5 eV. Magneto-optical spectra of polar Kerr rotation as well as the spectra of ellipsometric parameter Ψ exhibited significant changes when crossing the transformation temperature. These changes were assigned to different optical properties of Ni-Mn-Ga in martensite and austenite phases due to modification of electronic structure near the Fermi energy during martensitic transformation.
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3]
  1. Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 12116 Prague (Czech Republic)
  2. Laboratory of Engineering Materials, Aalto University, PL 14200, FIN-00076 Aalto (Finland)
  3. Institute of Physics ASCR, Na Slovance 2, 18221 Prague (Czech Republic)
Publication Date:
OSTI Identifier:
22409941
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; AUSTENITE; CUBIC LATTICES; ELECTRONIC STRUCTURE; ELLIPSOMETRY; FERMI LEVEL; GALLIUM ALLOYS; KERR EFFECT; MAGNETIZATION; MANGANESE ALLOYS; MARTENSITE; MONOCRYSTALS; NICKEL BASE ALLOYS; OPTICAL PROPERTIES; PHASE TRANSFORMATIONS; SHAPE MEMORY EFFECT; TEMPERATURE DEPENDENCE