17O NMR in planes and chains of YBa2Cu3O7

17O NMR in planes and chains of YBa2Cu3O7

2014 We report the first observation of 17O NMR spectra in YBa2Cu3O7 obtained after selective gas exchanges performed at 300 and 850°C. We are able to assign the narrow (weakly shifted) signal to the (1/2, 1/2) transition of oxygen atoms in CuO chains and the broad (strongly shifted) signal to the 0-sites in CuO2 planes. J. Phys. France 49 (1988) 1825-1828 NOVEMBRE 1988, Classification Physics,...

Effect of proximity coupling of chains and planes on the penetration-depth anisotropy in YBa2Cu3O7.

We calculate the penetration depth λ in the a, b and c directions for a simple model of YBa2Cu3O7. In this model there are two layers—representing a CuO2 plane and a CuO chain—per unit cell. There is a BCS–like pairing (both s wave and d wave are considered) interaction localised in the CuO2 planes. The CuO chains become superconducting at temperatures lower than Tc because of their proximity t...

NMR and Vortex Lattice Melting in YBa2Cu3O7

Homo- and heterometallic planes, chains and cubanes.

The synthesis, structural and magnetic characterisation of a family of homo- and heterometallic complexes constructed with the Schiff base ligands 2-iminomethyl-6-methoxy-phenol (L1H) and 2-imino-6-methoxy-phenol (L2H), are discussed. Members include the heterometallic tetranuclear complexes of general formula [Na2M2(X)2(L1)4(Y)2] (where M = Fe(III), X = (-)OMe, Y = NO3(-) (1) and M = Ni(II), X...

Solid-state NMR studies of 17O-enriched pyrophosphates.

For the first time, 17O NMR studies were performed on 17O-enriched crystalline pyrophosphates (magnesium-, sodium- and barium-pyrophosphate) by means of triple-quantum magic-angle spinning (3QMAS) and double-rotation (DOR) in the high external field of 17.6 T. Oxygen atoms in bridging positions (P-OB-P) exhibit a significant higher quadrupole coupling constant compared to oxygen atoms in termin...