Production of pulsed ultraslow muons and first mu SR experiments on thin metallic and magnetic films

Standard muon spin rotation (mu SR) spectroscopy implants 4 MeV spin-polari zed positive muons to investigate the bulk properties of matter. Success in producing epithermal muons opens interesting possibilities for studying ul trathin films, interfaces, and even surfaces. At the ISIS Facility, Rutherf ord Appleton Laboratory (Chilton, UK), we have produced a pulsed ultraslow muon beam (E < 20 eV) and have performed the first <mu>SR experiments. Due to the pulsed feature, the implantation time is automatically determined an d, by adjusting the final muon energy between about 8 and 20 eV, depth slic ing experiments are possible down to monolayers distances. We describe slic ing experiments across a 20 nm copper film on quartz substrate with evidenc e for a 2 nm copper oxide surface layer. A preliminary experiment on a hexa gonal cobalt film suggests the existence of muon precession in the local ma gnetic field. The results are discussed in relation to the morphological fe atures of the film.