Magnetoelectric quasi-(0-3) nanocomposite heterostructures.

Yanxi Li,Zhipeng Tian,Rong Sun,Jianjun Yao,Chunlin Chen,Dwight Viehland,Jiefang Li,Tiannan Yang,Zhiguang Wang,Zhongchang Wang,Jia-Mian Hu,Long-Qing Chen

doi:10.1038/ncomms7680

Abstract

Magnetoelectric composite thin films hold substantial promise for applications in novel multifunctional devices. However, there are presently shortcomings for both the extensively studied bilayer epitaxial (2-2) and vertically architectured nanocomposite (1-3) film systems, restricting their applications. Here we design a novel growth strategy to fabricate an architectured nanocomposite heterostructure with magnetic quasiparticles (0) embedded in a ferroelectric film matrix (3) by alternately growing (2-2) and (1-3) layers within the film. The new heteroepitaxial films not only overcome the clamping effect from substrate, but also significantly suppress the leakage current paths through the ferromagnetic phase. We demonstrate, by focusing on switching characteristics of the piezoresponse, that the heterostructure shows magnetic field dependence of piezoelectricity due to the improved coupling enabled by good connectivity amongst the piezoelectric and magnetostrictive phases. This new architectured magnetoelectric heterostructures may open a new avenue for applications of magnetoelectric films in micro-devices.

Highlights

Magnetoelectric composite thin films hold substantial promise for applications in novel multifunctional devices
On the micro- or nano-scale, the current phase connectivity architectures, which have been extensively studied for the ME composite thin films, can be summarized by two types: (i) vertical heteroepitaxial nanocomposites with nanorods of one phase embedded in a matrix of the other; and (ii) multilayering
There are shortcomings for both of these forms: the effective ME coupling of the (2-2) film connectivity is limited by the clamping of films to the substrate[22], while the low resistivity of the interconnected ferromagnetic phase of the (1-3) structure lowers the net resistivity of the composite layer, which in turn provides a path for dielectric leakage current

Summary

Introduction

Magnetoelectric composite thin films hold substantial promise for applications in novel multifunctional devices. Different from the previously reported (0-3) composites[23,24,25] with a randomly distributed magnetic phase component embedded in a matrix, the designed new structure has a somewhat orderly arranged magnetic nanorod particles with the same height and approximate similar planar area as those of the middle layer Such a new structure overcomes the clamping effect from the substrate of the (2-2) connectivity, while significantly reducing the leakage current paths through the ferromagnetic phase of the (1-3) structure. The connectivity amongst the constituent phases shows an improved ME coupling along the vertical direction due to the improved physical and electrical contact between piezoelectric and magnetostrictive phases on all sides, enhancing thereby the potential for ME effects This opens up a new avenue of approach for the ME heterostructures in microdevice applications

Methods

Results

Conclusion