dc leakage mechanism in artificial biferroic superlattices

Abstract

The dc leakage behavior of 0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃/La_0.6Sr_0.4MnO₃ asymmetric superlattices has been studied over a wide range of temperatures between 30 and 200° C. Leakage current characteristics analyzed in the light of different models indicated dominant Poole-Frenkel emission in the lower electric field region. Activation energy calculated from the Poole-Frenkel model was in the range of 0.19-0.34 eV for different superlattice periodicities. For the superlattices with lower periodicities (6 nm) dc leakage current in the low electric field region was dominated collectively by both Ohmic and Poole-Frenkel conduction mechanisms. At higher applied electric fields space charge limited conduction was found to be the dominant mechanism for all the superlattices. Realization of leakage mechanism over different temperatures and voltages can help in strategic interface engineering of these superlattices for device applications.