Ga site occupancy in HDDR-treated Nd2Fe14B-based alloy by XAFS

The changes of local structure far Ga in Nd13.0Fe68.2Co10.8Ga1.0Zr0.1B6.9 during hydrogenation, disproportionation, desorption and recombination (HDDR) process are studied by fluorescence XAFS in order to understand the evolution of magnetic anisotropy by HDDR process. Comparing the observed Ga XAFS data with the calculated ones, using ab initio calculation (FEEF), Ga is proved to occupy preferentially an Fe(c) site in the Nd2Fe14B structure before disproportionation and dissolves in alpha-Fe after the disproportionation. In the recombined state Ga redistributes into two phases, i.e. Nd2Fe14B and a Nd-rich phase. The behavior of Ga during the HDDR process differs from Zr which occupies Fe(j(2)) sites before disproportionation and after the disproportionation. (C) 1999 Elsevier Science S.A. All rights reserved.