Magnetoelectric Effect at the Ni/HfO₂ Interface Induced by Ferroelectric Polarization

Authors

Qiong Yang, University of Nebraska - LincolnFollow
Lingling Tao, University of Nebraska-LincolnFollow
Zhen Jiang, University of Nebraska - Lincoln
Yichun Zhou, Xiangtan University
Evgeny Tsymbal, University of Nebraska-LincolnFollow
Vitaly Alexandrov, University of Nebraska - LincolnFollow

Date of this Version

8-21-2019

Citation

PHYSICAL REVIEW APPLIED 12, 024044 (2019).

DOI: 10.1103/PhysRevApplied.12.024044

Comments

© 2019 American Physical Society. Used by permission.

Abstract

Driven by the technological importance of the recently discovered ferroelectric HfO₂, we explore a magnetoelectric effect at the HfO₂-based ferroelectric-ferromagnetic interface. Using density-functionaltheory calculations of the Ni/HfO₂/Ni (001) heterostructure as a model system, we predict a stable and sizable ferroelectric polarization in a few-nm-thick HfO₂ layer. For the Ni/HfO₂ interface with opposite polarization directions (pointing to or away from the interface), we find a sizable difference in the interfacial Ni—O bonding, resulting in dissimilar degrees of depletion of the electron density around the interface. The latter affects the relative population of the exchange-split majority and minority spin bands at the interface and thus the interfacial magnetic moments. The sizable change in the interface magnetization with ferroelectric polarization reversal of HfO₂ manifests a significant ferroelectrically induced magnetoelectric effect at the Ni/HfO₂ interface. Our results reveal promising prospects of ferroelectric-ferromagnetic composite multiferroics based on HfO₂-based ferroelectric materials.