Vortex ferroelectric domains, large-loop weak ferromagnetic domains, and their decoupling in hexagonal (Lu, Sc)FeO3

Abstract

The direct domain coupling of spontaneous ferroelectric polarization and net magnetic moment can result in giant magnetoelectric (ME) coupling, which is essential to achieve mutual control and practical applications of multiferroics. Recently, the possible bulk domain coupling, the mutual control of ferroelectricity (FE) and weak ferromagnetism (WFM) have been theoretically predicted in hexagonal LuFeO 3 . Here, we report the first successful growth of highly-cleavable Sc-stabilized hexagonal Lu 0.6 Sc 0.4 FeO 3 (h-LSFO) single crystals, as well as the first visualization of their intrinsic cloverleaf pattern of vortex FE domains and large-loop WFM domains. The vortex FE domains are on the order of 0.1-1 μm in size. On the other hand, the loop WFM domains are~100 μm in size, and there exists no interlocking of FE and WFM domain walls. These strongly manifest the decoupling between FE and WFM in h-LSFO. The domain decoupling can be explained as the consequence of the structure-mediated coupling between polarization and dominant in-plane antiferromagnetic spins according to the theoretical prediction, which reveals intriguing interplays between FE, WFM, and antiferromagnetic orders in h-LSFO. Our results also indicate that the magnetic topological charge tends to be identical to the structural topological charge. This could provide new insights into the induction of direct coupling between magnetism and ferroelectricity mediated by structural distortions, which will be useful for the future applications of multiferroics.

Microwave conductivity of ferroelectric domains and domain walls in a hexagonal rare-earth ferrite

“…MIM studies demonstrate that the microwave response of DWs is dominated by their vibrational dynamics, resulting in a bias-independent effective ac conductivity higher than the dc value by a factor of ~ 10 4 . As h-Lu0.6Sc0.4FeO3 is a room-temperature multiferroic material 23,34 , our results shed new lights on the interplay among electrical conduction, structural dynamics, ferroelectricity, and magnetism in small band-gap multiferroics. down domains 19 .…”

Seeing is believing: visualization of antiferromagnetic domains

“…29,30 The α-Fe 2 O 3 magnetic vortex/antivortex domains resemble crystallographic vortex/antivortex domains observed in, for example, hexagonal R(Mn,Fe) O 3 (R = rare earths), Fe 1/3 TaS 2 , and Ca 2 SrTi 2 O 7 . [31][32][33][34] It is a theoretical and experimental challenge to unveil such AFM vortex/antivortex domains.…”

Manipulation of Conductive Domain Walls in Confined Ferroelectric Nanoislands

“…If these additives are well understood and controlled, the FEDW conduction as a novel functionality would be offered an additional degree of freedom. In fact, recent studies did reveal some unique exotic domains such as bubble, flux‐closure vortex, and center‐type topological states in nanoscale ferroelectrics, which also add more ingredients into the enthralling DW functionalities. In view of the tantalizing properties in both domain wall conductance and nanoferroelectrics, it is highly promising and extremely important to look into the FEDW conduction behaviors in size‐confined nanostructures.…”