c-axis phase coherence and spin fluctuations in cuprates
Université Libre de Bruxelles - CP-232,
Blvd du Triomphe, B-1050 Brussels, Belgium
Accepted: 10 April 2001
There is a consensus that superconductivity (SC) in cuprates is two-dimensional. It is widely believed that the long-range phase coherence appears at Tc due to the Josephson coupling between SC CuO2 (bi-, tri-, ...) layers. Recent Tc and resistivity measurements in Tl2Ba2CaCu2O8 as a function of applied pressure (Salvetat J.-P. et al., Europhys. Lett., 52 (2000) 584) show that the interlayer Josephson-coupling mechanism does not fit the data. Here we analyze data obtained in Andreev reflection, neutron scattering, microwave, muon spin relaxation, tunneling and resistivity measurements performed on different cuprates, mainly, on YBa2Cu3O, Bi2Sr2CaCu2O and LaSrxCuO. The analysis of the data shows that the long-range phase coherence in the cuprates intimately relates to antiferromagnetic interactions along the c-axis. At the same time, it seems that the in-plane mechanism of SC has no or little relations to the magnetic interactions along the c-axis.
PACS: 74.25.-q – Superconductivity: General properties; correlations between physical properties in normal and superconducting state / 74.72.-h – High-Tc compounds / 74.25.Ha – Magnetic properties
© EDP Sciences, 2001