mu SR studies of elemental boron, modelling interstitial protons with implanted positive muons

Studies of positive muons implanted into solid elemental boron illustrate t he various mu SR techniques of muon spin rotation, relaxation and resonance . The chemical behaviour of positive muons and protons being similar, the l ocal magnetic dipole and electrical quadrupole interactions with the boron nuclei determined by these measurements should characterize the crystallogr aphic site and electronic structure of interstitial protons. Muon diffusion through the boron lattice becomes significant only above 500 K, with an ac tivation energy of 0.33(2) eV, as determined from motional narrowing of the rotation spectrum and evolution of the zero-field relaxation function. The strong spin-spin couplings in boron prove suitable for demonstrating vario us techniques of radiofrequency and level-crossing resonance, and also a no vel form of spin echo detected in null external field. Copyright (C) 2000 J ohn Wiley & Sons, Ltd.