In-plane and out-of-plane correlations in Ho(1-x)YxMnO3

TL;DR

This study investigates magnetic phase competition in Ho(1-x)YxMnO3 using neutron scattering, revealing fluctuations between phases that may influence magnetic-ferroelectric coupling in these multiferroic materials.

Contribution

It provides new insights into phase competition and magnetic fluctuations in Ho(1-x)YxMnO3, linking these phenomena to magnetic-ferroelectric coupling.

Findings

Quasielastic scattering indicates phase fluctuations at domain boundaries.

Strong phase competition exists even in pure YMnO3.

Fluctuations may influence magnetic-ferroelectric coupling.

Abstract

Strong magnetic-ferroelectric coupling in hexagonal HoMnO3 has been observed previously at spin reorientation temperature between P6'3cm' and the P6'3cm' magnetic phases. In contrast, YMnO3 has only a single magnetic phase (P6'3cm') and no sign of strong magnetic-ferroelectric coupling. In order to investigate the P6'3cm' to P6'3c'm spin reorientation transition, single crystals of Ho(1-x)YxMnO3 at varying compositions were grown. Neutron scattering measurements reveal quasielastic scattering in the YMnO3-like phase (P6'3c'm) centered on the Bragg peak corresponding to HoMnO3-like phase (P6'3cm') and vice versa. This scattering may be due to short-lived fluctuations into the "wrong" magnetic phase at domain boundaries. These results suggest that there is strong phase competition between the P6'3cm' and P6'3c'm phases even in pure YMnO3, and this competition may play an important role in the magnetic-ferroelectric coupling observed in HoMnO3.