Nanopowders of R2Fe14B-type compounds in high magnetic fields: The effects of substitutional and interstitial atoms on inter-sublattice exchange interaction

The fundamental magnetic characteristics of R 2 Fe 14 B intermetallics are highly sensitive to atomic substitutions and interstitial absorption of light elements. In this work, both were combined, and the influence of the substitutions in the R-sublattice and hydrogen absorption on the magnetization of (RR’) 2 Fe 14 BH x (R is Tm or Er, and R’ is Nd) in magnetic fields up to 58T was studied. (Tm 0.5 Nd 0.5 ) 2 Fe 14 B and (Er 0.5 Nd 0.5 ) 2 Fe 14 B were prepared. By using direct hydrogen absorption, (R 0.5 Nd 0.5 ) 2 Fe 14 BH x compounds were obtained with hydrogen content Magnetic measurements of both the parent alloys and their hydrides were carried out on nanopowders. The strength of the inter-sublattice coupling in (Tm 0.5 Nd 0.5 ) 2 Fe 14 B, (Er 0.5 Nd 0.5 ) 2 Fe 14 B and their hydrides is estimated by analysing high-field magnetization data. Itis shown that hydrogenation weakens the inter-sublattice exchange interaction up to 45 %. (Tm 0.5 Nd 0.5 ) 2 Fe 14 B, with the maximum hydrogen content of 5.5 at.H/f.u., reaches the field-induced ferromagnetic state at about 55 T.