Magnetovolume effects in Dy2Fe17-xMnx
We have investigated the structural and magnetic properties of Dy2Fe17−xMnx compounds (x=0–5.0)(x=0–5.0) by X-ray diffraction, linear thermal expansion (LTE) and magnetization measurements. Compared with Dy2Co17−xMnx compounds for which a linear increase of the unit cell volume with increasing Mn fraction is found, the composition dependence of the unit cell volume in the Dy2Fe17−xMnx series exhibits a relative maximum around x∼0.5 before increasing monotonically for x⩾2; this behaviour can be ascribed to the existence of spontaneous volume magnetostriction as confirmed by LTE measurements. The Curie temperature (Tc) remains essentially constant (around 370 K) for Mn content up to x=1x=1 before decreasing steadily with increasing x, down to TC=232 K for Dy2Fe12Mn5. The 3d-sublattice magnetization decreases monotonically with increasing Mn content.