Magnetovolume effect in Ho2Fe17-xMnx compounds

The structural and magnetic properties of seven compounds in the Ho2Fe17-xMnx series (x = 0-5) have been investigated. The spontaneous magnetization Ms at 10 K exhibits a minimum at x ≈ 3.8 while the 3d-sublattice magnetization MT is found to decrease at ∼ −3.4 μB/per Mn atom compared with the rate of ∼−2.0 μB/per Mn atom expected from a simple dilution model. All of the Ho2Fe17-xMnx compounds exhibit anisotropic thermal expansion below their Curie temperatures leading to the presence of strong magnetovolume effects and Invar-type behavior below TC. An approximately zero volume thermal expansion has been detected between 10 K and 270 K for Ho2Fe17. The maximum magnetic entropy changes for Ho2Fe17-xMnx with x = 0 and 2.0 are 3.2 J kg−1K−1 around TC ∼ 336 K and 2.7 J kg−1 K−1 around TC ∼ 302 K, respectively, for magnetic field change of B = 0-5 T.