Interface Engineering of Domain Structures in BiFeO₃ Thin Films

Abstract

A wealth of fascinating phenomena have been discovered at the BiFeO domain walls, examples such as domain wall conductivity, photovoltaic effects, and magnetoelectric coupling. Thus, the ability to precisely control the domain structures and accurately study their switching behaviors is critical to realize the next generation of novel devices based on domain wall functionalities. In this work, the introduction of a dielectric layer leads to the tunability of the depolarization field both in the multilayers and superlattices, which provides a novel approach to control the domain patterns of BiFeO films. Moreover, we are able to study the switching behavior of the first time obtained periodic 109° stripe domains with a thick bottom electrode. Besides, the precise controlling of pure 71° and 109° periodic stripe domain walls enable us to make a clear demonstration that the exchange bias in the ferromagnet/BiFeO system originates from 109° domain walls. Our findings provide future directions to study the room temperature electric field control of exchange bias and open a new pathway to explore the room temperature multiferroic vortices in the BiFeO system.

Monoclinic (K,Na)NbO3 Ferroelectric Phase in Epitaxial Films

“…[32,33] Figure 2a-d presents PFM amplitude and phase images along both the in-plane (IP) and out-of-plane (OP) directions. [32,33] Figure 2a-d presents PFM amplitude and phase images along both the in-plane (IP) and out-of-plane (OP) directions.…”

“…PFM technique is a powerful tool to reveal the ferroelectric polarization orientation and domain structure . Figure a–d presents PFM amplitude and phase images along both the in‐plane (IP) and out‐of‐plane (OP) directions.…”

Probing Ferroic States in Oxide Thin Films Using Optical Second Harmonic Generation

“…Screening conditions affect the stability of domain walls and are a key parameter in the control of complex domain structures. By inserting a dielectric layer between the ferroelectric thin film and the metallic buffer, the 109 • stripe domain state could be favored in BFO [62] and 180 • domains were stabilized in PbTiO 3 (PTO) [63,64]; see Figure 2d,e, respectively.…”

Tuning Effective Spin Hall Angles via Oxygen Vacancies in Multiferroic BiFeO3‐Based Heterostructures

“…For its ferroelectricity at room temperature, BFO has been widely studied . An antisymmetric DMI in BFO gives rise to a weak ferromagnetic moment, which is usually used for magnetoelectric coupling and may induce the field‐free SOT switching. However, the DMI coupling can only occur in some special situations .…”