RIS ID
40170
Abstract
The structural and magnetic properties of Dy2Fe17−xMnx (x=0–5) compounds have been investigated using x-ray diffraction, linear thermal expansion, magnetization measurements, and 57Fe Mössbauer spectroscopy. Compared with Dy2Co17−xMnx compounds for which a linear increase of the unit-cell volume V with increasing Mn fraction is found, the compositional dependence of the lattice parameters of Dy2Fe17−xMnx first exhibits a slight maximum around x=0.5 before increasing monotonically with further increase in x; this behavior can be ascribed to a spontaneous magnetostriction as confirmed by linear-thermal-expansion measurements. The Curie temperature TC remains essentially unchanged for Mn contents up to x=1 [TC=370(4) K for x=0.0, TC=373(4) K for x=1.0] before decreasing steadily with further increase in Mn content [TC=232(4) K for Dy2Fe12Mn5]. The rapid decrease of spontaneous magnetization and the essentially constant value of TC for lower Mn concentrations can be understood in terms of the two-sublattice model and by considering the preferential site occupation of Mn atoms in the Dy2Fe17−xMnx unit cell. The exchange interaction between the rare-earth and transition-metal sublattices has been investigated by means of a mean-field analysis of the high-field magnetization isotherms which were measured on the powder samples. The 57Fe hyperfine interaction parameters of the Dy2Fe16Mn1 and Dy2Fe14Mn3 samples have been determined from the Mössbauer spectra (5–300 K).
Publication Details
Wang, J., Campbell, S. J., Tegus, O., Marquina, C. and Ibarra, M. R. (2007). Magnetovolume effect and magnetic properties of Dy2Fe17â¿xMnx. Physical Review B (Condensed Matter and Materials Physics), 75 (17), 174423-1-174423-10.