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 P42/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, TC, increases with a modest Al substitution in spite of little changes in the saturation magnetization Ms. However, both TC and Ms decrease for a higher Al substitution. All the specimens have negative K1 and positive K2. The easy axis of magnetization is parallel to the [100] direction since K1+2K2<0 is satisfied for all the specimens. Although the magnitude of K1+2K2 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.