Year: 1993
Type: conference-paper
Abstract: Oxygen doped La{sub 2}CuO{sub 4+{delta}}, due to the unusually large mobility of the oxygen ions at high temperatures, is the only cuprate which has macroscopic phase separation of doped holes. We discuss our studies of La{sub 2}CuO{sub 4+{delta}}, including phase separation, distributed local structure whose onset coincides with-phase separation and the observation that in the presence of doped holes two distinct copper sites copper sites are generated, an observation which contrasts with results of diffraction studies. The superconducting transition temperature Tc in this material changes by over 10% in response to altered cooling history. Below a temperature T{sub f}, the situation becomes similar to other cuprates since oxygen is no longer sufficiently mobile to allow further macroscopic phase separation. In this regime the magnetic behavior of metallic La{sub 2}CuO{sub 4+{delta}} is conventional in context of cuprates. However {sup 139}La NMR spectroscopy has shown the local structure of the La-O layer to be very sensitive to the presence of doped holes and to be strongly temperature dependent in this same regime. This sensitivity is evident in the CuO{sub 2} planes where, in the presence of doped holes a second, distinct copper site is present. This provides an opportunity to explore the relationship between local structure and the novel magnetic behavior of the cuprates.
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Los Alamos National Laboratory
OpenAlex ID: W2298575455