We have studied the excess oxygen content and hole concentration in 110 ± C annealed La 2 CuO 41d prepared by electrochemical oxidation for 0 , d , 0.12. Two distinct sites were observed with doping efficiency of 2 or 1.3 holes per excess oxygen atom. The occupation of the two different sites is determined by a critical carrier concentration P c ഠ 0.06. As a consequence, a sudden increase of chemical potential of doped holes at P c is suggested. [S0031-9007(96)
Superconducting phases in La2Cu04+ & prepared at ambient temperature by electrochemical oxidation have been investigated for the nominal composition range 0(6'(0.1. Consistent with previous reports, a stable superconducting phase with T, -32-34 K is observed for 6~0.05. In contrast, samples with 8&0.05 are found to be unstable either at room temperature or upon annealing between 25 C and 110 C. All phases with
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.