The influence of atomic order on the magnetic and structural properties of the ferromagnetic shape memory compound Ni2MnGa

• Published in: Journal of physics. Condensed matter 2003-06, Vol.15 (22), p.3831-3839
• Main Authors: Kreissl, M, Neumann, K-U, Stephens, T, Ziebeck, K R A
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic properties and materials; Martensitic transformations; Materials science; Metals. Metallurgy; Other ferromagnetic metals and alloys; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Studies of specific magnetic materials
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/15/22/317

The effect of atomic order on the martensitic phase transition and magnetic properties of stoichiometric Ni2MnGa has been investigated in a sample quenched from 1000DGC. Magnetization, resistivity and x-ray diffraction measurements indicate that the structural phase transition occurs at ~103 K, substantially lower than the value reported for samples quenched from 800DGC and ordered in the Heusler L21 structure. A small reduction in the ferromagnetic moment was also observed, although the Curie temperature remained largely unaffected. The electronic Sommerfeld coefficient obtained from heat capacity measurements is enhanced but smaller than that observed for the 800DGC quenched sample. The results are consistent with band structure calculations and the electronic changes brought about by atomic disorder.