Distribution of antiferromagnetic rare-earth domains in multiferroic Dy_0.7Tb_0.3FeO₃

In many multiferroics, rare-earth and transition-metal orders coexist. For analyzing their interaction and its consequences for the multiferroic state, the domain patterns and their spatial correlation give valuable insight. Unfortunately, this is often hampered by the lack of access to the domains of the rare-earth order. Here, we uncover such a domain pattern for the multiferroic Dy_0.7Tb_0.3FeO₃. Optical second harmonic generation reveals columnar Dy/Tb domains. The columns arrange perpendicular to the magnetically induced electric polarization. Hence, the antiferromagnetic rare-earth order forces the ferroelectric domains to form nominally charged domain walls. In turn, to reduce energy, the ferroelectric order causes a diminished rare-earth domain-wall density along the polarization direction. This interplay highlights the multiferroic character of the Dy_0.7Tb_0.3FeO₃ domain pattern and the important role of the rare-earth order. We position Dy_0.7Tb_0.3FeO₃ within the broader landscape of rare-earth multiferroics identifying three distinct scenarios for the role of rare-earth order.