Program Highlights

Elucidating Single-ion Magnetic Anisotropy in LuFeO₃ 

Xiaoshan Xu, Peter A. Dowben, and Evgeny Y. Tsymbal, Shi Cao, Xiaozhe Zhang,
Tula R Paudel, Kishan Sinha, and Xuanyuan Jiang  
 Nebraska MRSEC

Multiferroic materials carry spontaneous electric and magnetic dipole moments simultaneously which makes them promising for the application in energy efficient information technologies. This is due to the coupling between the electric and magnetic dipole moments, which may enable voltage controlled switching of the magnetization. Lutetium ferrite, LuFeO₃, is one of the multiferroic materials whose spontaneous magnetic moment relies on its preferred orientation on the atomic site. This property, known as the single-ion magnetic anisotropy, is difficult to elucidate due to a small energy scale controlling its behavior.

Nebraska MRSEC researchers have revealed the origin of the single-ion magnetic anisotropy in LuFeO₃. Using collaborative efforts in thin film growth, x-ray absorption spectroscopy, and density functional theory, they demonstrated that the local symmetry of the iron ion (Fe³⁺) sites determines this property. They found that for both hexagonal and orthorhombic LuFeO₃ (shown in the figure) the small distortion of the crystal structure changes the local symmetry of the Fe³⁺ ions and thus alters the orientation of their magnetic moments.  This result is important because it suggests a route for tuning magnetism in multiferroic materials, like LuFeO₃, by the fine adjustment of their crystal structures, as well as a route in coupling the electricity and magnetism via structural distortions.

These programs are supported by the National Science Foundation, Division of Materials Research, Materials Research Science and Engineering Program, Grant DMR-1420645.

Crystal structures of hexagonal (left) and orthorhombic (right) LuFeO₃. Arrows indicate orientations of the magnetic moments on the Fe sites.