The role of ferroelectric-ferromagnetic layers on the properties of superlattice-based multiferroics

摘要

A series of superlattices and trilayers composed of ferromagnetic and ferroelectric or paraelectric layers were grown on (100) SrTiO_3 by the pulsed-laser deposition technique. Their structural and magnetoelectric properties were examined. The superlattices made of ferromagnetic Pr_(0.85)Ca_(0.15)MnO_3 (PCMO) and a ferroelectric, namely, Ba_(0.6)Sr_(0.4)TiO_3 (BST) or BaTiO_3, showed enhanced magnetoresistance (MR) at high applied magnetic field, whereas such enhancement was absent in Pr_(0.85)Ca_(0.15)MnO_3/SrTiO_3 superlattices, which clearly demonstrates the preponderant role of the ferroelectric layers in this enhanced MR. Furthermore, the absence of enhanced MR in trilayers of PCMO/BST indicates that the magnetoelectric coupling which is responsible for MR in these systems is stronger in multilayers than in their trilayer counterparts.