Surface Studies with Hyperfine Probes

Abstract

Recently interesting experiments have been reported where hyperfine techniques, like nuclear magnetic resonance (NMR) /1/, Mössbauer spectroscopy /2,3/ and perturbed angular correlations (PAC) /4,5/, have been applied to study surface phenomena. Especially PAC has proven to be rather powerful since surfaces can be prepared with an extremely low probe concentration, i.e. surfaces can be labelled with isolated radioactive probes. In such cases the hyperfine parameters, like the electric field gradient acting at the probe nuclei, can serve as a fingerprint to elucidate different probe sites at the surface, impurity-probe configurations and diffusion of impurities. The most recent review on the subject /6/, presented at the HFI-VII conference in Bagalore, India, shall be updated and a short section about PAC interface work will be appended.