The influence of Zr doping on the structure, vacancy defects, and magnetic properties of GdMnO3 ceramics

The influences of the Zr doping on the structure, vacancy defects, and magnetic properties of GdMn1-xZrxO3 (x = 0.00-0.20) ceramic samples synthesized using a solid-state reaction method were investigated. All the GdMn1-xZrxO3 samples formed a single-phase structure, and no phase transformation occurred within the experimental doping range; however, Zr doping caused lattice distortion. The microstructure of the GdMn1-xZrxO3 samples was compact, and Zr doping reduced the grain size. The positron annihilation spectrum (PAS) measurements showed that Zr doping had a great influence on the cation vacancy concentration of GdMn1-xZrxO3 samples. The vacancy concentration increased with increasing Zr doping content from 0.00 to 0.10, and then decreased with the further increase in Zr doping content. XPS results showed that the charge compensation induced by Zr doping was achieved mainly by the decrease of cation valence (forming Mn2+) in the x = 0.00-0.10 ceramics. Appropriate Zr doping obviously improved the transition temperatures and magnetization of the GdMn1-xZrxO3 samples. This investigation demonstrated that the cation vacancy concentration is one of the important factors that could tailor the magnetic properties of GdMn(1-x)Zr(x)O(3)ceramics.