Small angle neutron scattering studies of critical correlations in alloys (invited)

Abstract
Neutron small angle scattering (SAS) data are compared and contrasted for three different types of transition metal alloys which display a critical concentration cF for the onset of ferromagnetism. In Cr Fe alloys and in amorphous (Fe Mn) PC alloys near cF the scattering intensity rises dramatically below the Curie temperature. This ‘‘subcritical’’ scattering is not found in Pd Ni alloys. While the physics of the onset of order is quite different in the three cases, the behavior of the correlation range as a function of temperature and concentration is very similar in the three alloy systems.