Inelastic Neutron Scattering from MnF2in the Critical Region

Abstract

Detailed neutron-scattering measurements have yielded the behavior of the scattering function $S(q, \omega )$ for both the transverse and longitudinal fluctuations in the critical region of the uniaxial antiferromagnet Mn${\mathrm{F}}_2$. The static wavelength-dependent susceptibilities are measured both above and below $T_N$. The relaxation rates for the longitudinal fluctuations are found to be correctly described by dynamical scaling both above and below $T_N$. The scaling functions ${\Omega }_{\pm }\left(\frac{q}{\kappa }\right)$ applying respectively above and below $T_N$ are determined explicitly.