Magnetic and structural properties of the magnetic shape memory compound Ni2Mn1.48Sb0.52

• Published in: Journal of physics. Condensed matter 2010-03, Vol.22 (9), p.096002-096002
• Main Authors: Brown, P J, Gandy, A P, Ishida, K, Ito, W, Kainuma, R, Kanomata, T, Neumann, K U, Oikawa, K, Ouladdiaf, B, Sheikh, A, Ziebeck, K R A
• Format: Article
• Language: English
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Domain effects, magnetization curves, and hysteresis; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Ferromagnetism; Magnetic moment; Magnetic properties and materials; Magnetization; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Manganese; Martensitic transformations; Phase transformations; Physics; Shape memory; Solid-solid transitions; Specific phase transitions
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/22/9/096002

Magnetization and high resolution neutron powder diffraction measurements on the magnetic shape memory compound Ni2Mn1.48Sb0.52 have confirmed that it is ferromagnetic below 350 K and undergoes a structural phase transition at TM310 K. The high temperature phase has the cubic L21 structure with a = 5.958 A, with the excess manganese atoms occupying the 4(b) Sb sites. In the cubic phase above 310 K the manganese moments are ferromagnetically aligned. The magnetic moment at the 4(a) site is 1.57(12) Delta *mB and it is almost zero (0.15(9) Delta *mB) at the 4(b) site. The low temperature orthorhombic phase which is only fully established below 50 K has the space group Pmma with a cell related to the cubic one by a Bain transformation aorth = (acub + bcub)/2; borth = ccub and corth = (acub - bcub). The change in cell volume is 2.5%. The spontaneous magnetization of samples cooled in fields less than 0.5 T decreases at temperatures below TM and at 2 K the magnetic moment per formula unit in fields up to 5.5 T is 2.01(5) Delta *mB. Neutron diffraction patterns obtained below 132 K gave evidence for a weak incommensurate magnetic modulation with propagation vector (2/3, 1/,0).