SMALL-ANGLE NEUTRON-SCATTERING STUDIES OF CE(FE1-XALX)2

Ce(Fe1-xAlx)2, with x=0, 0.06, and 0.14, has been studied by small-ang le neutron scattering in order to investigate the instability of the f erromagnetic state in the pure material to small amounts of magnetic d isorder. The pure material (x=0) displays a ferromagnetic transition n ear T(C)=225 K, and more complicated behavior below approximately 100 K. The disordered alloys, x=0.06 and x=0.14, display ferromagnetic-lik e states over relatively narrow temperature ranges, and an additional low-temperature phase. The ferromagnetic-like state in the x=0.14 allo y appears to be qualitatively different from that exhibited by the oth er two. High-wave-vector-resolution measurements on the x=0.06 sample indicate that its low-temperature ordered phase is ferrimagnetic in or igin.