MUON BONDING AND ANTIFERROMAGNETISM IN THE 123 CUPRATES

Muon Spin Relaxation (μSR) is a microscopic technique which may help in understanding the mechanism of superconductivity in the high-temperature cuprates. A computational study indicates muon-probe sites in RBa2Cu3Ox are strongly dependent on the oxygen content (x), however, these μ sites are nearly independent of the rare earth (R). For x = 7, the majority of the μ sites lies near oxygen in the basal planes; for x = 6, near the oxygens in the CuO planes. The results are based upon potential-energy calculations using the Ewald method, ionic potentials and two different Morse-like potentials describing the μ-O bonding. Magnetic dipole fields are calculated for the candidate μ sites and compared with available zero-field μSR data. The obtained good agreement indicates that the ionic bonding assumption may be correct in describing the electronic p- and d-states in the insulating and superconducting cuprates. © 1990.