Magnetic anisotropy of Sm2Fe17-xGax hydrides

The magnetic properties of single-phase 2:17 compounds of the composition Sm2Fe17−xGaxHy were investigated. The substitution of Ga for Fe in the Sm2Fe17 compound resulted in a substantial increase in the Curie temperature and, for alloys with x > 2, the formation of a uniaxial magnetic anisotropy at room temperature. The diffusion of hydrogen into those compounds that exhibit an easy axis anisotropy causes a transition back to a planar anisotropy. This indicates that the presence of interstitial hydrogen is detrimental to the hard magnetic properties of these materials.