Simultaneous imaging of the ferromagnetic and ferroelectric structure in multiferroic heterostructures

J Unguris,R Ramesh,S R Bowden,M Trassin,S.-W Cheong,S Fackler,I Takeuchi,D T Pierce

doi:10.1063/1.4890055

Abstract

By measuring the spin polarization of secondary electrons and the intensity of backscattered electrons generated in a scanning electron microscope, we are able to simultaneously image the ferromagnetic domain structure of a ferromagnetic thin film and the ferroelectric domain structure of the underlying ferroelectric substrate upon which it is grown. Simultaneous imaging allows straightforward, quantitative measurements of the correlations in these complex multiferroic systems. We have successfully imaged domains in CoFe/BFO and Fe/BTO, two systems with very different ferromagnet/ferroelectric coupling mechanisms, demonstrating how this technique provides a new local probe of magneto electric/strictive effects in multiferroic heterostructures.

Highlights

Combining ferromagnetic and ferroelectric materials has produced exciting new opportunities to design and produce structures with new functionalities.[1,2,3] In particular, heteroepitaxially grown ferromagnetic/ferroelectric multilayers provide a potential path towards making nanodevices where the magnetization is electrically controlled through magnetoelastic or magnetoelectric coupling.[4,5,6]
We demonstrate the simultaneous imaging of ferromagnetic and ferroelectric structure in multiferroic multilayers using a modified scanning electron microscope (SEM)
The low energy secondary electrons are spin-polarized and provide information about the direction of the magnetization in the ferromagnetic film, while the high energy elastically scattered electrons are sensitive to crystal structure and lattice distortions and the electric polarization direction in the underlying ferroelectric substrate

Summary

Introduction

Combining ferromagnetic and ferroelectric materials has produced exciting new opportunities to design and produce structures with new functionalities.[1,2,3] In particular, heteroepitaxially grown ferromagnetic/ferroelectric multilayers provide a potential path towards making nanodevices where the magnetization is electrically controlled through magnetoelastic or magnetoelectric coupling.[4,5,6]. The low energy secondary electrons are spin-polarized and provide information about the direction of the magnetization in the ferromagnetic film, while the high energy elastically scattered electrons are sensitive to crystal structure and lattice distortions and the electric polarization direction in the underlying ferroelectric substrate.

Results

Conclusion