Abstract
The oxygen doping of lanthanum cuprate to generate superconductiving La
2CuO
4+
δ
(0<δ≦0.032) has been studied by high-pressure, isotopic-oxygen enrichment and thermal desorption mass spectroscopy (TDMS). Isotopic data show that the additional oxygen incorporated under high pressure readily exchanges with ionic lattice oxygen during enrichment at 860 K. The thermal release of the excess oxygen from superconducting crystals above ∼ 350 K is not bulk diffusion limited. An alternate explanation for the observed rapid O
2(g) bursts is proposed.