The structural, dielectric, and magnetic properties of GdMnO3 multiferroic ceramics

GdMnO3 (GMO) ceramics were prepared by solid-state reaction method, the structure, defects, dielectric, and magnetic properties of GMO ceramics sintered at different temperatures have been studied. Characterization by XRD indicates that impurity phase-free GMO can be synthesized at 1350 °C. SEM measurements show that the grain size of GMO increases and the microstructure becomes denser with increasing sintering temperature. Positron annihilation results reveal that the vacancies concentration decreases when sintering temperature increases from 1300 to 1350 °C, and then increases when sintering temperature increases from 1350 to 1400 °C. Dielectric measurements indicate that the GMO ceramic sintered at 1350 °C presents higher dielectric constant and smaller dielectric loss. Magnetic properties measurements show that the magnetic properties of GMO can be modulated by sintering temperature. The relation between structure and properties implies that the cation vacancy defect has remarkable effects on the dielectric and magnetic properties of GMO.