THE EFFECT OF ABSORBED HYDROGEN ON THE MAGNETIC-PROPERTIES OF DYFE11TI

The effect of absorbed hydrogen on the structural and magnetic properties of DyFe11Ti has been investigated. The compound DyFe11Ti was hydrogenated to the composition DyFe11TiHx, where x ranges from 0 to 1.5. The absorption hydrogen pressure-composition isotherms of the hydrides indicate solid solution behavior. Hydrogen absorption does not change the tetragonal structure of the host compound but is accompanied by an expansion in unit cell volume. Magnetic characteristics of the host material and its hydrides (measured in situ in a hydrogen atmosphere) were investigated over the temperature range 77-700 K and at applied fields up to 12 kOe. Upon hydrogenation the magnetic ordering temperature T-c as well as the spin-reorientation temperatures T-sr are observed to increase. Moreover, the incorporation of hydrogen leads to an expansion of the temperature range in which the magnetic anisotropy of the rare-earth sublattice dominates over that of the iron sublattice.