  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 LuFeO3. Here, we report the first successful growth of
highly-cleavable Sc-stabilized hexagonal Lu0.6Sc0.4FeO3 (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 {\mu}m in size. On the other hand, the loop WFM
domains are ~100 {\mu}m 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.
