Scientists suggest engineering metal-organic multiferroics at room temperature

Recently, a research group led by Professor Li Xiangyang of Hefei Institutes of Physical Sciences (HFIPS), Chinese Academy of Sciences (CAS), theoretically predicted a series of multiferroic materials that can be applied in high-temperature environments. ambient using d–p spin coupling combined with central symmetry breaking organic heterocycles in Cr-based two-dimensional (2D) metal-organic structures.

The research results were published in Nano Letters.

Multiferroic materials, characterized by the coexistence of two or three ferroic orders, have become an essential research platform, driving advancements in the fields of information storage, sensing technologies, electronics and energy conversion. The advent of 2D materials has revitalized the field of multiferroics, promising finer, more efficient, and more versatile functionality. However, despite substantial progress in this area, the number of 2D multiferroics with room temperature magnetism remains particularly rare.

To overcome this challenge, researchers proposed a novel approach to obtain 2D multiferroics at room temperature in 2D metal-organic frameworks (MOFs) by exploiting dp spin coupling combined with central symmetry breaking six-membered heterocyclic ligands.

Using this method, they examined 128 different 2D MOFs and discovered three unique multiferroic materials: Cr(1,2-oxazine)2, Cr(1,2,4-triazine)2, and Cr(1,2,3,4 – trazine)2. All of these materials exhibit ferrimagnetism as well as ferro/antiferroelectricity at room temperature. The ferrimagnetic order at room temperature is thought to arise from the strong direct dp spin coupling between Cr cations and ligand anions.

Specifically, Cr(1,2-oxazine)2 exhibits ferroelectric characteristics, while the latter two exhibit antiferroelectric properties. Impressively, each of these materials has suitable barriers for polarization switching.

“Our study provided a promising platform for the design of 2D multiferroic materials at room temperature,” said Professor LI Xiangyang.