A study of polymer-derived erbia-doped Bi2O3 nanocrystalline ceramic powders

In this study, erbia (Er2O3)-doped Bi2O3 ceramics were prepared from sol-gel derived nanocrystalline powders. The morphological properties were investigated by scanning electron microscopy. X-ray diffraction (XRD) analysis was carried out in order to characterize the phase and crystal structure of the powder samples. Temperature dependent electrical properties were determined by thermogravimetry/differential thermal analyzer (TG/DTA) and 4-point probe techniques. The stable fluorite face centered cubic delta-type phase was observed at room temperature from the XRD result, which was supported by the DTA and temperature dependent electrical conductivity measurements. Electrical conductivity results indicate that there is a transition approximately at 650 A degrees C, which can be attributed to an order-disorder transition (ODT). The activation energy values obtained from the Arrhenius approach for heating and cooling process were presented. Two regimes, corresponding to high temperature region (HTR) and low temperature region (LTR), were observed. As a result of morphological changes during the ODT, the electrical conductivity modifies and the activation energies are different for studied sample at HTR and LTR.