Impacts of Mn-deficiency on the structure and physical properties of GdMnO3 ceramics

The effects of Mn-deficiency on the structure, Mn ions valence, vacancy defects, magnetic and dielectric characteristics of GdMn1−xO3 ceramics synthesized by solid-state reaction were investigated. The results revealed that Mn-deficiency caused the lattice deformation, but had no effect on the orthorhombic perovskite structure of all GdMn1−xO3 samples. Raman analysis showed that Mn-deficiency induced octahedral distortions and lattice disorder and affected < Mn–O > length. XPS analysis implied that the valence state of Mn ion evolved in GdMn1−xO3 samples owing to the charge compensation. Positron annihilation lifetime spectroscopy revealed that the vacancy size and concentration increased with increasing Mn-deficiency concentration x. The properties measurements showed that the Mn-deficiency increased the relative dielectric permittivity and magnetization of GdMnO3 system. The relationship between structure and performances was discussed in this paper.