Magnetic properties of Sm(Fe1-xAlx)7 crystals

Sm(Fe1-xAlx)(7) (x=0, 0.047, 0.07 and 0.12) crystals were grown by the self-flux method, and their crystallographic and magnetic properties were investigated. Sm(Fe1-xAlx)(7) crystallizes in a tetragonal structure of the space group P4(2)/mnm, and aluminum occupies the iron site. The structure is very similar to that of Nd2Fe14B except that the boron sites are vacant. The Curie temperature, T-C, increases with a modest Al substitution in spite of little changes in the saturation magnetization M-s. However, both T-C and M-s decrease for a higher Al substitution. All the specimens have negative K-1 and positive K-2. The easy axis of magnetization is parallel to the [100] direction since K-1 + 2K(2) < 0 is satisfied for all the specimens. Although the magnitude of K-1 + 2K(2) decreases and becomes closer to zero with increasing Al content, aluminum substitution seems to be ineffective to change the easy direction from the basal plane to the c-axis. (C) 2000 Elsevier Science S.A. All rights reserved.