The structural, electric, and magnetic properties of bulk hexagonal $\mathrm{LuFe}{\mathrm{O}}_3$ are investigated. Single phase hexagonal $\mathrm{LuFe}{\mathrm{O}}_3$ has been successfully stabilized in the bulk form without any doping by sol-gel method. The hexagonal crystal structure with $P{6}_{3}cm$ space group has been confirmed by x-ray-diffraction, neutron-diffraction, and Raman spectroscopy study at room temperature. Neutron diffraction confirms the hexagonal phase of $\mathrm{LuFe}{\mathrm{O}}_3$ persists down to 6 K. Further, the x-ray photoelectron spectroscopy established the 3+ oxidation state of Fe ions. The temperature-dependent magnetic dc susceptibility, specific heat, and neutron-diffraction studies confirm an antiferromagnetic ordering below the Néel temperature $\left(T_{\mathrm{N}}\right)\sim 130\mathrm{K}$. Analysis of magnetic neutron-diffraction patterns reveals an in-plane ($ab$-plane) ${120}^{\circ }$ antiferromagnetic structure, characterized by a propagation vector $k=\left(000\right)$ with an ordered moment of $2.84{\mu }_{\mathrm{B}}/\mathrm{F}{\mathrm{e}}^{3+}$ at 6 K. The ${120}^{\circ }$ antifferomagnetic ordering is further confirmed by spin-orbit coupling density functional theory calculations. The on-site coulomb interaction ($U$) and Hund's parameter $\left(J_H\right)$ on Fe atoms reproduced the neutron-diffraction ${\mathrm{\Gamma }}_1$ spin pattern among the Fe atoms. $P\text{−}E$ loop measurements at room temperature confirm an intrinsic ferroelectricity of the sample with remnant polarization $P_{\mathrm{r}}\sim 0.18\mu \mathrm{C}/\mathrm{c}{\mathrm{m}}^2$. A clear anomaly in the dielectric data is observed at $\sim T_{\mathrm{N}}$ revealing the presence of magnetoelectric coupling. A change in the lattice constants at $T_{\mathrm{N}}$ has also been found, indicating the presence of a strong magnetoelastic coupling. Thus a coupling between lattice, electric, and magnetic degrees of freedom is established in bulk hexagonal $\mathrm{LuFe}{\mathrm{O}}_3$.

• Received 27 November 2017
• Revised 15 March 2018

DOI:https://doi.org/10.1103/PhysRevB.97.184419