Measurements of the point contact tunnelling spectra of the superconductors La,-,Sr,CuO,-, and EuBa,Cu,O, with Nb were performed. The superconducting gap A at 4.2 K with a ratio 2A/Tc of about 10 was obtained. The structure of the tunnelling spectra at voltages above the gap shows that pairing originates from the electron-electron interaction via phonons and possibly via some other excitations of electronic nature with energy about 100 meV.
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