Investigation of scaling laws by critical neutron scattering from beta-brass

Using a Cu65-Zn β-brass crystal, the critical scattering of neutrons has been studied, both above and below T c. The staggered susceptibilities χ vary as C+(T/Tc-1)-γ and C-(1-T/Tc)-γ ', respectively. It is found that γ=γ' within an accuracy of 3%, in agreement with the scaling hypothesis of static critical phenomena; and that C+/C-=5.46±0.05, in excellent agreement with the recent parametric representation theory of Schofield and in fair agreement with the results of series expansions by Essam and Hunter.

For fixed q, a flat maximum is observed in the wave-vector-dependent susceptibility χ(q, T) at temperatures which agree well with the predictions of Fisher and Burford (1967)