Gas effusion spectra have been obtained in the temperature range 30-1000 °C for underdoped, optimized, and overdoped (Formula presented)(Formula presented) samples. We observe a large oxygen multipeak structure at high temperatures and a wide low-intensity oxygen “tail” at lower temperatures. The two lowest-temperature oxygen peaks are believed to originate from bonding sites for excess oxygen. The δ values derived from these two peaks are consistent with δ values derived from neutron powder diffraction (NPD). The wide low-temperature oxygen tail in the effusion spectra suggests the existence of loosely bound disordered oxygen in overdoped samples and accounts for the discrepancy between δ values determined by NPD and thermogravimetry analysis. Our results provide further evidence that each doping oxygen atom contributes, on average, only about one carrier to the (Formula presented) plane in (Formula presented)(Formula presented).
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - 1996
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics