HYDROGEN-INDUCED PHASE-SEPARATION IN LA1.89SR0.11CUO4 AS REVEALED BY EPR OF FE SPIN PROBES

EPR measurements of Fe3+ spin probes doped to La1.89Sr0.11CuO4 superco nductor were carried out to study the hydrogen absorption effect on th is compound. In the high-temperature region the EPR linewidth was dete rmined by the Korringa relaxation. By extracting the Korringa contribu tion, we were able to evaluate a dependence of the density of states a t the Fermi surface N(E(F)) on hydrogen concentration. It has been fou nd that N(E(F)) is unchanged during the hydrogenation process. An anal ysis of the EPR spectra shows that hydrogen doping induces phase separ ation of the compound, creating insulating, magnetically ordered regio ns in a metallic, superconducting background. Copyright (C) 1996 Elsev ier Science Ltd