Longitudinal fluctuations in an isotropic ferromagnet

Abstract
The neutron scattering cross section due to the longitudinal fluctuations above and below the Curie temperature in a crystal of palladium 10% iron has been identified with the aid of neutron-spin polarisation analysis. The cross section is observed to be quasielastic, with an intensity which is a maximum at Tc, and which diminishes with increasing wavevector, increasing applied field, and decreasing temperature below Tc.