Slow dynamics in hard condensed matter: a case study of the phase separating systemNdNiO3

Abstract

We report the time dependent response of electrical resistivity in the non-magnetic perovskite oxideNdNiO3 in its phase separated state and provide a physical explanation of the observations. We alsomodel the system and make an accurate Monte Carlo simulation of the observed behavior.While cooling, a phase separation takes place in the system below its metal–insulatortransition temperature and in this state the material exhibits various dynamical phenomenasuch as relaxation of resistivity, dependence of resistivity on cooling rate and rejuvenationof the material after ageing. These phenomena signal that the phase separated state ofNdNiO3 is not in thermodynamic equilibrium, and we conjecture that it consists of supercooledparamagnetic metallic and antiferromagnetic insulating phases. The supercooled phases aremetastable and they switch over to the insulating equilibrium state stochastically, and thiscan account for the slow dynamics observed in our system. We also verify the predictivepower of our model by simulating the result of a new experiment and confirming it byactual measurements.