Realization of biferroic properties in La_0.6Sr_0.4MnO₃/0.7Pb(Mg_1/3Nb_2/3)O₃-0.3(PbTiO₃) epitaxial superlattices

Abstract

A set of symmetric and asymmetric superlattices with ferromagnetic La_0.6Sr_0.4MnO₃ (LSMO) and ferroelectric 0.7Pb(Mg_1/3Nb_2/3)O₃-0.3(PbTiO₃) as the constituting layers was fabricated on LaNiO₃ coated (100) oriented LaAlO₃ substrates using pulsed laser ablation. The crystallinity, and magnetic and ferroelectric properties were studied for all the superlattices. All the superlattice structures exhibited a ferromagnetic behavior over a wide range of temperatures between 10 and 300 K, whereas only the asymmetric superlattices exhibited a reasonably good ferroelectric behavior. Strong influence of an applied magnetic field was observed on the ferroelectric properties of the asymmetric superlattices. Studies were conducted toward understanding the influence of conducting LSMO layers on the electrical responses of the heterostructures. The absence of ferroelectricity in the symmetric superlattice structures has been attributed to their high leakage characteristics. The effect of an applied magnetic field on the ferroelectric properties of the asymmetric superlattices indicated strong influence of the interfaces on the properties. The dominance of the interface on the dielectric response was confirmed by the observed Maxwell-Wagner-type dielectric relaxation in these heterostructures.