Magnetic properties of Sm(Fe1−xAlx)7 crystals

Abstract Sm(Fe 1− x Al x ) 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(Fe 1− x Al x ) 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 Nd 2 Fe 14 B 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 +2 K 2 K 1 +2 K 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.