Time evolution of resistance in response to magnetic field: Evidence of glassy transport in La0.85Sr0.15CoO3.

We demonstrate the distinct glassy transport phenomena associated with the phase separated and spin-glass-like phases of La_0.85Sr_0.15CoO₃, prepared under different heat-treatment conditions. The low-temperature annealed (phase-separated) sample, exhibits a small change in resistance, with evolution of time, as compared to the high-temperature annealed (spin glass) one. However, the resistance change as a function of time, in both cases, is well described by a stretched exponential fit, signifying the slow dynamics. Moreover, the ultraviolet spectroscopy study evidences a relatively higher density of states in the vicinity of E_F for low-temperature annealed sample and this correctly points to its less semiconducting behavior. [ABSTRACT FROM AUTHOR]