In the field of spintronics, multiferroics are materials in which ferroelectric and magnetic orders coexist. The coupling of these properties, called magnetoelectric, allows to manipulate spin states under the effect of an electric field, and to modify dielectric properties under a magnetic field. Scientists from the Rennes Institute of Chemical Sciences (University of Rennes/CNRS/ENSCR/INSA Rennes) have computationally predicted that copper oxide would become multiferroic at room temperature under a pressure of about 20 GPa. This computational work, published in Nature Communications and Physical Review B, was recently confirmed experimentally by an international consortium in Physical Review Letters.
Spintronics is a recent technology exploiting the magnetic and quantum properties of the electron. Within this field, many research investigations aim at discovering multifunctional materials where magnetism and ferroelectricity coexist. These materials, called multiferroics, are very rare. Among the known compounds, few exhibit properties adapted to an industrial application, such as digital memories smaller and consuming less energy than those currently available. The two main challenges to their realization are to have materials that work at room temperature and offer optimal responses (strong electric polarization that can be reversed).
In this context, scientists from the Institute of Chemical Sciences of Rennes, based on quantum calculations and Monte-Carlo simulations, have predicted that the compound CuO would become multiferroic at room temperature if exposed to a pressure of 20 GPa1. Motivated by this theoretical prediction made in 2013, several research groups around the world embarked on experimental studies of CuO under high pressure. Recently, experimental evidence was established by an international consortium from high-pressure neutron diffraction measurements and published in Physical Review Letters! More precisely, this paper shows that at about 18.5 GPa CuO is multiferroic at room temperature. This is a remarkable technical achievement that required the use of several modified high-pressure cells to reach the highest pressures and temperatures.
1. This pressure is 200,000 times greater than that of the atmosphere.To give an idea, it is obtained in the earth's upper mantle at a depth of about 160 km. Experimentally, this involves the use of a diamond anvil cell.
- Room-temperature spin-spiral multiferroicity in high-pressure cupric oxide
X. Rocquefelte, K. Schwarz, P. Blaha, S. Kumar, J. Van Den Brink
Nature Communications, 2013, 4, 2511
- Potential room-temperature multiferroicity in cupric oxide under high pressure
W. Lafargue-Dit-Hauret, D. Braithwaite, A. D. Huxley, T. Kimura, A. Saúl, X. Rocquefelte
Physical Review B, 2021, 103(21), 214432
- Room-Temperature Type-II Multiferroic Phase Induced by Pressure in Cupric Oxide
N. Terada, D. D. Khalyavin, P. Manuel, F. Orlandi, C. J. Ridley, C. L. Bull, R. Ono, I. Solovyev, T. Naka, D. Prabhakaran, A. T. Boothroyd
Physical Review Letters, 2022, 129, 217601
Xavier Rocquefelte, Univ Rennes, CNRS, ISCR-UMR 6226, 35000 Rennes, France
xavier [dot] rocquefelteuniv-rennes1 [dot] fr
Published January 16, 2023