Intrinsic magnetic centers and microdomains in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 6.5} and TmBa{sub 2}Cu{sub 3}O{sub 6+x}
- Magnetic Resonance Laboratory, Kazan State University, 420008 Kazan (Russia)
- Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9506, 2300 RA Leiden (The Netherlands)
- Laboratoire de Physique des Solides, Universite de Paris-Sud, 91405 Orsay Cedex (France)
We measured the influence of magnetic centers (MC{close_quote}s) on the nuclear relaxation in 123 compounds using {sup 169}Tm NMR and {sup 63}Cu NQR in TmBa{sub 2}Cu{sub 3}O{sub 6+x} (x=0, 0.2, 0.3, 0.4, 0.5, 0.6), and {sup 89}Y NMR and {sup 63}Cu NQR in YBa{sub 2}Cu{sub 3}O{sub 6.5}. Particular attention is paid to the region 0.5{le}x{le}0.6 in order to deal with both a well-defined ortho II structure and a high enough MC concentration. The experiments reveal a two-component nuclear relaxation in the superconducting compounds at temperatures above 1 K, especially pronounced in the x=0.5 samples. The relaxation data give evidence for microphase separation due to oxygen disorder in the basal CuO{sub x} planes. In the well-annealed samples, the MC{close_quote}s predominating the relaxation have S=1/2. The concentrations of these MC{close_quote}s are of the order of 3{percent} in the disordered (nonsuperconducting) microphase and {approximately}0.3{percent} in the ordered (superconducting) one. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 496750
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 55, Issue 17; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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