SmallAngle Critical Magnetic Neutron Scattering from Cobalt.
Abstract
Detailed measurements were made of the smallangle scattering of neutrons from cobalt in the vicinity of its Curie temperature, T sub c. Through the use of total and inelastic scattering techniques, both the small wave vector and low frequency dependence of the scattering function in the critical region were determined. Below T sub c the scattering is dominated by welldefined spinwave modes which exhibit nearly quadratic dispersion. A simple generalization of hydrodynamic expressions for the spinwave crosssection gives a satisfactory description of observed line shapes at all temperatures below T sub c. Above T sub c, the angular distributions of the critical scattering are found to be well described by the OrnsteinZernike form for the reduced wavevectordependent susceptibility after taking full account of the inelasticity of the scattering. The results obtained are compared with predictions of the theories of static and dynamic scaling as well as with calculations of critical properties based on the Heisenberg and Ising models.
 Publication:

Ph.D. Thesis
 Pub Date:
 1975
 Bibcode:
 1975PhDT........23G
 Keywords:

 Physics: Condensed Matter;
 Cobalt;
 Curie Temperature;
 Neutron Scattering;
 Angular Distribution;
 Hydrodynamics;
 Inelastic Scattering;
 SolidState Physics