Microstructure and Properties of Well-Ordered Multiferroic Pb(Zr,Ti)O₃/CoFe₂O₄ Nanocomposites

Abstract

A nanofabrication technique combining pulsed laser deposition and a nanoporous anodic aluminum oxide membrane mask is being proposed to prepare various types of multiferroic nanocomposites, viz. periodically ordered CoFe(2)O(4) dots covered by a continuous Pb(Zr,Ti)O(3) layer, Pb(Zr,Ti)O(3) dots covered with CoFe(2)O(4), and Pb(Zr,Ti)O(3)/CoFe(2)O(4) bilayer heterostructure dots. By properly tuning the processing parameters, epitaxial nanodot-matrix composites can be obtained. For the composite consisting of CoFe(2)O(4) nanostructures covered by a Pb(Zr,Ti)O(3) film, an unexpected out-of-plane magnetic easy axis induced by the top Pb(Zr,Ti)O(3) layer and a uniform microdomain structure can be observed. The nanocomposites tested by piezoresponse force microscopy (PFM) exhibit strong piezoelectric signals, and they also display magnetoelectric coupling revealed by magnetic-field dependent capacitance measurement.