Fluctuations

We have earlier proposed models of preformed hole pairs based on the results of our electron pa-ramagnetic resonance experiments. A hole doped in a cuprate superconductor causes ferromag-netic alignment of the spins of the holes of 4 Cu2+ ions of the plaquette (CuO)4 in which it enters. Spin alignments undergo oscillations from vertically upward to vertically downward of the CuO2 plane. Vertical projections of spins go on changing when they pass through different plaquettes going to zero when they pass through the CuO2 plane. Ferromagnetic alignments of spins produce magnetic fields on the plane proportional to their vertical projections. When two holes travelling in CuO2 plane come across each other at a certain distance between them, they are attracted to-wards each other by Heisenberg exchange interaction and their path is decided by the magnetic field produced due to spin alignments. Their path is similar to 2 23dx y − atomic orbital. Y-123 has been chosen as an example. Due to plethora of evidence of antiferromagnetic fluctuations in cu-prates, hole-pair formation has been tried in Y-123 assuming antiferromagnetic fluctuations in it. It has been found that hole-pair formation in spite of AFM fluctuations can be explained on the same lines as done earlier. Hole-pair formation was tried in Tl-2201 to test whether the sam