Incommensurate modulated structure of the ferromagnetic shape-memory Ni{sub 2}MnGa martensite

Journal Article · Wed Nov 15 00:00:00 EST 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.07.005· OSTI ID:20900894

Righi, Lara ^[1]; Albertini, Franca ^[2]; Calestani, Gianluca ^[1]; Pareti, Luigi ^[2]; Paoluzi, Antonio ^[2]; Ritter, Clemens ^[3]; Algarabel, Pedro A ^[4]; Morellon, Luis ^[4]; Ricardo Ibarra, M ^[4]

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1. Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universita di Parma, Viale delle Scienze, I-43100 Parma (Italy)
2. IMEM, Consiglio Nazionale delle Ricerche, Parco Area delle Scienze 37/A, I-43010 Fontanini, Parma (Italy)
3. Intitut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)
4. Departamento de Fisica de la Materia Condensada-ICMA, Universidad de Zaragoza CSIC, 50009 Zaragoza (Spain)

The ferromagnetic shape memory (MSM) alloy Ni{sub 2}MnGa undergoes a martensitic transformation (MT) at T=220 K on cooling. The structure of this phase is studied by powder X-ray diffraction experiment. The analysis of the experimental data combined with the huge information reported in literature allowed to conclude that the Ni{sub 2}MnGa martensite shows an incommensurate modulated structure closely related to a five-fold layered superstructure. The symmetry of the basic structure is found to be orthorhombic. The structure is refined by Rietveld method with superspace group Immm(00{gamma})s00 having a=4.2187(1) A, b=5.5534(1) A and c=4.1899(1) A and modulation vector q=0.4248(3)c*. The results show that the modulation is mainly related to the periodic shuffling of the atomic layers perpendicular to the c-axis of the orthorhombic basic structure. - Graphical abstract: Perspective view of the L2{sub 1} cubic structure of Ni{sub 2}MnGa austenite. The dotted lines define the basic structure of the incommensurate modulated martensite.

• OSTI ID: 20900894
• Journal Information: Journal of Solid State Chemistry, Vol. 179, Issue 11; Other Information: DOI: 10.1016/j.jssc.2006.07.005; PII: S0022-4596(06)00379-3; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
EXPERIMENTAL DATA
GALLIUM ALLOYS
MANGANESE ALLOYS
MARTENSITE
NICKEL ALLOYS
PHASE TRANSFORMATIONS
SHAPE MEMORY EFFECT
TETRAGONAL LATTICES
X-RAY DIFFRACTION