A new type of magnetoelectric (ME) effect was discovered in Tb1-xGdxMn2O5 in which Gd ions are substituted into TbMn2O5. The substitution of Gd ions increased to x=0.5 was found to completely suppress increases in electric polarization below T∼14K, which is clearly observed in TbMn2O5. The electric polarization of Tb0.5Gd0.5Mn2O5 reappears below T∼14K in response to an external magnetic field applied along each crystallographic axis. This isotropic ME effect is in distinction from those exhibited by the RMn2O5 family and by other multiferroic compounds. Resonant x-ray scattering was used to investigate the mechanism of the ME effect, and the data clearly demonstrate that this phenomenon can be attributed to competition between two different magnetic orderings. Furthermore, the magnetic-field dependence of the resonant intensity around the O K edge implies that charge transfer between O and Mn ions microscopically contributes to the ME effects. These findings indicate potential new applications for multiferroic materials.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics