C-axis tunneling in Bi2Sr2CaCu2O8+δ in the magnetic field up to 60 T

We report on the c-axis resistivity rho (c)(H) in Bi2Sr2CaCu2O8+delta (Bi-2212) that exhibits a maximum in quasistatic magnetic fields up to 60 T. We show that below T-c c-asis tunneling is a parallel, two-channel process: (i) sigma (j) of Cooper pairs and (ii) sigma (q) of quasiparticles: sigma (c) = sigma (j) + sigma (q). We demonstrate that high-field c-axis conductivity is linear-in-field at H < H-c2, in agreement with the field-linear dependence of quasiparticle conductivity <sigma>(q) we find in mesas. Near GO T, as temperature decreases, rho (c) saturates, confirming a gapless spectrum of quasiparticles. The linear rho (c)(H) behavior extends up to the maximum field in experiment (GOT), beyond the applicability of the Fermi-liquid approach, which can be due to effects of the pseudo gap, not accounted in the model.