Muon spin relaxation in condensed oxygen

The magnetic structure and dynamics of condensed oxygen are investigated by means of muon spin relaxation in longitudinal and zero fields. Explicit calculations of the dipolar and hyperfine fields at the muon preferential sites elucidate the local electronic structure around the muon probe and allow interpretation of the precession frequency found in zero-field experiments on the magnetically ordered alpha-phase. The temperature dependence of the relaxation rates in the phases devoid of magnetic long-range order is analysed in terms of the fast paramagnetic fluctuations quantified in previous neutron spectroscopy experiments.