Abstract
The hexagonal rare-earth ferrite family represents a unique class of multiferroics exhibiting weak ferromagnetism, and a strong coupling between magnetism and structural trimerization is predicted. However, the hexagonal structure for remains metastable in conventional conditions. We have succeeded in stabilizing the hexagonal structure of polycrystalline by partial Sc substitution of Yb. Using bulk magnetometry and neutron diffraction, we find that orders into a canted antiferromagnetic state with the Néel temperature , below which the moments form the triangular configuration in the plane and their in-plane projections are parallel to the [100] axis, consistent with magnetic space group . It is determined that the spin canting is aligned along the axis, giving rise to the weak ferromagnetism. Furthermore, the moments reorient toward a new direction below reorientation temperature , satisfying magnetic subgroup , while the moments order independently and ferrimagnetically along the axis at the characteristic temperature . Interestingly, reproducible modulation of electric polarization induced by magnetic field at low temperature is achieved, suggesting that the delicate structural distortion associated with two-up/one-down buckling of the Yb/Sc planes and tilting of the bipyramids may mediate the coupling between ferroelectric and magnetic orders under magnetic field. The present work represents substantial progress to search for high-temperature multiferroics in hexagonal ferrites and related materials.
1 More- Received 11 November 2020
- Revised 19 March 2021
- Accepted 26 April 2021
DOI:https://doi.org/10.1103/PhysRevB.103.174102
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