New discovery could lead to more memory storage in electronics

Researchers have discovered rare materials known as multiferroics that possess both controllable magnetic and electric polarisation properties at near-room temperatures.

The discovery could lead to longer battery life and increased memory storage for electronic devices, said Yurong Yang, a research assistant professor at the University of Arkansas. The materials can change their electrical polarisation when under a magnetic field or magnetic properties when under an electric field. But multiferroics usually exhibit these properties at temperatures far below room temperature, which makes them useless for everyday applications. As a result, the materials used to power today’s memory devices do so through electricity or magnetism, but not both.

The research team included Yang and Laurent Bellaiche, Distinguished Professor of physics at the University of Arkansas. Yang, a theoretical physicist, used computer modelling to perform extremely accurate calculations on a specific class of materials to find combinations that would display these properties.

The researchers found that a specific class of multiferroics, when periodically alternating along a specific direction to make what is called a superlattice, should exhibit both controllable magnetic and electrical polarisation properties at near-room temperature, Yang said.

Superlattices are like multilayered cakes, where the cake layers are only nanometres thick and are made of different materials such as the multiferroics studied in this paper. The next step will be experimental confirmation of their calculations. Yang and Bellaiche both conduct research in the University of Arkansas’s Institute for Nanoscience and Engineering and the department of physics. Bellaiche holds the Twenty-First Century Endowed Professorship in Nanotechnology and Science Education.

The results were obtained through a collaborative effort with Hong Jian Zhao, a former visiting graduate student at the University of Arkansas who is now completing his doctorate in the department of materials science and engineering at Zhejiang University in Hangzhou, China. Also collaborating on the study were Xiang Ming Chen, Zhao’s adviser at Zhejiang University; Wei Ren at Shanghai University in China; and Jorge Iniguez at the Materials Science Institute of Barcelona in Spain.