High-temperature (T>200 K) 139La NMR relaxation rates in single crystals of La2CuO4+? (?~0.015 and ?~0.002) at two measuring frequencies are presented and compared with zero-field NQR data for a series of La2-x Sr x CuO4+? powder samples with 0<=x<=0.08 and 0<?0.013. For ??0 an enhancement of the relaxation rate is observed which is related to the time dependence of the quadrupole interaction. Quantitative information on the oxygen diffusion is obtained from the analysis of the data with a simple diffusion model. The results are discussed in relation to the problem of macroscopic phase separation occurring for higher oxygen content.
139La NMR-NQR study of the oxygen diffusion in La2-x Sr x CuO4+?
S Rubini;
1994
Abstract
High-temperature (T>200 K) 139La NMR relaxation rates in single crystals of La2CuO4+? (?~0.015 and ?~0.002) at two measuring frequencies are presented and compared with zero-field NQR data for a series of La2-x Sr x CuO4+? powder samples with 0<=x<=0.08 and 0File in questo prodotto:
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