ALUMINUM SITE OCCUPATION IN Y2FE14-XALXB

Neutron diffraction has been used to study a series of Y2Fe14-xAlxB so lid solutions with x=0.65, 0.92, 1.30, 1.53, and 1.93. Aluminum atoms are found to occupy the j(2) and c sites. The Al site affinity appears to,be determined by the steric effect (j2) or crystal environment (c) . The c lattice parameter increases as the aluminum content x increase s, while the a lattice parameter decreases as the aluminum content x i ncreases. The unit cell volume increases as the aluminum content x inc reases, at a rate around 3 Angstrom(3) per Al atom per formula unit, m uch lower than observed in the Al substituted 2:17 compound. The avera ge Fe site moment decreases as the aluminum content x increases due to the reduction of the Fe content.