Magnetoelectric domain engineering from micrometer to {\AA}ngstr{\o}m scales

TL;DR

This paper demonstrates that chemical substitution in hexagonal manganites can precisely control ferroelectric domain sizes from micrometers down to Ångström scales while preserving magnetoelectric coupling, advancing domain engineering techniques.

Contribution

It introduces a method to engineer ferroelectric domain sizes in multiferroic hexagonal manganites from micrometer to Ångström scales via Mn$^{3+}$ to Al$^{3+}$ substitution, maintaining magnetoelectric coupling.

Findings

Domain size can be tuned from micrometers to Ångströms.

Magnetoelectric coupling remains intact despite substitution.

Chemical substitution is effective for domain engineering.

Abstract

The functionality of magnetoelectric multiferroics depends on the formation, size, and coupling of their magnetic and electric domains. Knowing the parameters guiding these criteria is a key effort in the emerging field of magnetoelectric domain engineering. Here we show, using a combination of piezoresponse-force microscopy, non-linear optics, and x-ray scattering, that the correlation length setting the size of the ferroelectric domains in the multiferroic hexagonal manganites can be engineered from the micron range down to a few unit cells under the substitution of Mn$^{3+}$ ions with Al$^{3+}$ ions. The magnetoelectric coupling mechanism between the antiferromagnetic Mn$^{3+}$ order and the distortive-ferroelectric order remains intact even at substantial replacement of Mn$^{3+}$ by Al$^{3+}$. Hence, chemical substitution proves to be an effective tool for domain-size engineering in one of the most studied classes of multiferroics.