Neutron scattering and magnetization measurements on the Kondo compound CeAl3

Previous measurements on the Kondo compounds, CdAl3 (hex- agonal DO19), indicate that with decreasing temperature it transforms gradually into a singlet state and does not magnetically order greater than 0.60K. To determine the spatial extent of the magnetic moment the spin-dependent cross-section of neutrons diffracted from the (201) planes of a polycrystalline sample in 50 kOe at 5, 19, and 810K was measured. At 50 kOe and these temperatures the total moment from magnetization measurements on the same sample is only 5 to 15 percent lower than the moment determined by the neutrons if a 4f form factor is assumed. This approximate agreement supports the hypothesis that the moment decreases without changing its spatial distribution. A similar spatially uniform reduction of the moment occurs also in dilute Kondo systems. From the field dependence of the magnetization M, the characteristic or Kondo temperature is estimated to be 5.10K