Hyperfine Interactions in Magnetic Materials by γ-γ Angular Correlation Measurements

Abstract

A method for measuring hyperfine interactions in magnetic materials by γ-γ angular correlation techniques is discussed. The change in the anisotropy of the 1415-122 Kev γ-γ angular correlation following the K capture of ${\mathrm{Eu}}^{152}$ in neutron irradiated polycrystalline samples of Europium iron garnet enriched in ${\mathrm{Eu}}^{151}$ has been measured as a function of temperature without applied magnetic field, and the rotation of the angular correlation pattern has been observed when a magnetic field was applied perpendicular to the plane containing the γ counters. From these experiments, the effective magnetic field acting at the Europium nuclei immediately after the radioactive decay can be obtained.