Exploring the Magnetoelectric Coupling at the Composite Interfaces of FE/FM/FE Heterostructures

Dhiren K Pradhan,A K Pradhan,Rama K Vasudevan,J Marty Gregg,Sergei V Kalinin,Ram S Katiyar,Evgheni Strelcov,Ashok Kumar,Shalini Kumari,Dillip K Pradhan,Venkata S Puli

doi:10.1038/s41598-018-35648-1

Abstract

Multiferroic materials have attracted considerable attention as possible candidates for a wide variety of future microelectronic and memory devices, although robust magnetoelectric (ME) coupling between electric and magnetic orders at room temperature still remains difficult to achieve. In order to obtain robust ME coupling at room temperature, we studied the Pb(Fe0.5Nb0.5)O3/Ni0.65Zn0.35Fe2O4/Pb(Fe0.5Nb0.5)O3 (PFN/NZFO/PFN) trilayer structure as a representative FE/FM/FE system. We report the ferroelectric, magnetic and ME properties of PFN/NZFO/PFN trilayer nanoscale heterostructure having dimensions 70/20/70 nm, at room temperature. The presence of only (00l) reflection of PFN and NZFO in the X-ray diffraction (XRD) patterns and electron diffraction patterns in Transmission Electron Microscopy (TEM) confirm the epitaxial growth of multilayer heterostructure. The distribution of the ferroelectric loop area in a wide area has been studied, suggesting that spatial variability of ferroelectric switching behavior is low, and film growth is of high quality. The ferroelectric and magnetic phase transitions of these heterostructures have been found at ~575 K and ~650 K, respectively which are well above room temperature. These nanostructures exhibit low loss tangent, large saturation polarization (Ps ~ 38 µC/cm2) and magnetization (Ms ~ 48 emu/cm3) with strong ME coupling at room temperature revealing them as potential candidates for nanoscale multifunctional and spintronics device applications.

Highlights

IntroductionResearchers have proceeded to design and develop artificial composite nanostructures to achieve large polarization and magnetization with strong ME coupling above room temperature[1,7,8,9]
The Pb(Fe0.5Nb0.5)O3 (PFN)/Ni0.65Zn0.35Fe2O4 (NZFO)/Pb(Fe0.5Nb0.5)O3 (PFN) trilayer heterostructure has been chosen for the present study to observe enhanced ferroelectric and magnetic properties with strong ME coupling above room temperature
The distribution of the ferroelectric loop area is almost uniform in a wide area, suggesting that spatial variability of ferroelectric switching behavior is low, and film growth is of high quality

Summary

Introduction

Researchers have proceeded to design and develop artificial composite nanostructures to achieve large polarization and magnetization with strong ME coupling above room temperature[1,7,8,9]. Magnetic materials with high magnetostriction, high Curie temperature (Tc), and large magnetization, as well as ferroelectric materials with large polarization, dielectric constant and piezoelectric coefficients, are required to produce strong ME coupling in the heterostructures[8,9,11]. The Pb(Fe0.5Nb0.5)O3 (PFN)/Ni0.65Zn0.35Fe2O4 (NZFO)/Pb(Fe0.5Nb0.5)O3 (PFN) trilayer heterostructure has been chosen for the present study to observe enhanced ferroelectric and magnetic properties with strong ME coupling above room temperature. We have investigated the ferroelectric and magnetic phase transition, tip induced polarization switching and ME coupling properties of PFN/NZFO/PFN at room temperature. The observation of strong ME coupling at room temperature make this nanostructure a potential candidate for multifunctional and spintronics nanoscale device applications

Methods

Results

Conclusion