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

Studies of positive muons implanted into solid elemental boron illustrate the various mu SR techniques of muon spin rotation, relaxation and resonance. The chemical behaviour of positive muons and protons being similar, the local magnetic dipole and electrical quadrupole interactions with the boron nuclei determined by these measurements should characterize the crystallographic site and electronic structure of interstitial protons. Muon diffusion through the boron lattice becomes significant only above 500 K, with an activation 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 various techniques of radiofrequency and level-crossing resonance, and also a novel form of spin echo detected in null external field. Copyright (C) 2000 John Wiley & Sons, Ltd.