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For the first time, Neel, the winner of the Nobel Prize, has applied sublattice theory to explain the magnetism of multicomponent systems. Within the bioscillation electron model a superconducting phase transition in the crystal AB is accomplished by break valence ties, the formation of paired electrons or molecule sublattices of A2 and B2: 2AB=A2+B2. Energy Φ balance equations are 2Φ2[AB]≤Φ2[A2]+Φ2[B2], Φ2[AB]≤Φ2[A2], Φ2[AB]≤Φ2[B2]. The mechanism of the superconducting phase transition in the yttrium-barium YBaCuO or other cuprates under poly oscillation electron model is examined. In the first stage there are formed yttrium, barium (or other elements) and copper oxides, in the second stage the oxides are dissociated. The molecules are formed, provided that the atom association energy is more gap energy of valence bonds in oxides. Calculations of quadratic energies for the oxides and cuprates to room temperature and 90K are performed. To superconducting phase transition has been occurred, the quadratic energy must be greater than the criterion. The cuprate with a stoichiometric composition is not a superconductor according to experimental data. The balance equations at 90K are consistent with the experimental data 406.4256*2 ─ (328.482+400.6432) = 83.726 eV2. The total quadratic energy required for education Y2 and Ba2 molecules is equal to 812.8512 eV2. Cuprates with the introduction of additional oxygen typeYBa2Cu3O6.5 + 0.5 are superconductors. The energies of the valence bonds are reduced the introduction of oxygen above stoichiometric values by expanding crystal lattice.
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