Cupric oxide as an induced-multiferroic with high-TC
Abstract
Materials that combine coupled electric and magnetic dipole order are termed `magnetoelectric multiferroics'. In the past few years, a new class of such materials, `induced-multiferroics', has been discovered, wherein non-collinear spiral magnetic order breaks inversion symmetry, thus inducing ferroelectricity. Spiral magnetic order often arises from the existence of competing magnetic interactions that reduce the ordering temperature of a more conventional collinear phase. Hence, spiral-phase-induced ferroelectricity tends to exist only at temperatures lower than ~40K. Here, we propose that copper(II) oxides (containing Cu2+ ions) having large magnetic superexchange interactions can be good candidates for induced-multiferroics with high Curie temperature (TC). In fact, we demonstrate ferroelectricity with TC=230K in cupric oxide, CuO (tenorite), which is known as a starting material for the synthesis of high-Tc (critical temperature) superconductors. Our result provides an important contribution to the search for high-temperature magnetoelectric multiferroics.
- Publication:
-
Nature Materials
- Pub Date:
- April 2008
- DOI:
- 10.1038/nmat2125
- Bibcode:
- 2008NatMa...7..291K