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 M-s at 10 K exhibits a minimum at x approximate to 3.8 while the 3d-sublattice magnetization M-T is found to decrease at similar to -3.4 mu(B)/per Mn atom compared with the rate of similar to -2.0 mu(B)/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 T-C. 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(-1) K-1 around T-C similar to 336 K and 2.7 J kg(-1) K-1 around T-C similar to 302 K, respectively, for magnetic field change of B = 0-5 T. (C) 2012 American Institute of Physics. [doi:10.1063/1.3671422]