Possible increase in the critical temperature of high-temperature superconductors based on the synthesis of new classes of HTSC compounds

The effect of exchange enhancement of electron-phonon interactions in high-temperature superconductor (HTSC) systems is examined and an upper bound is determined for applicability of the quasilinear equations. The spin-phonon interaction in the HTSC phase is described. It is found that if the resonance wave vector k(rez) << p(F), then use of the quasilinear equations is justified, since k(rez) is on the order of the inverse correlation length k(c) which, in turn, does not exceed the inverse coherence length (i.e., k(c) << p(F)). Thus, the quasilinear calculation of T-c is correct when the spin-phonon coupling parameter xi >> 1 and can be used to determine the synthesis characteristics for new HTSC materials with higher T-c. Published by AIP Publishing.