Dielectric loss anomaly of BaBiO3

Dielectric properties of oxygen deficient BaBiO3-delta have been analyzed, and dielectric loss anomalies at 175 and 225 K were found, which were depen dent on oxygen deficiency. The activation energies corresponding to the rel axation processes of dielectric anomalies at 175 and 225 K were 0.26 and 0. 50 eV, respectively. The dielectric anomaly at 175 K is believed to be caus ed by hole movement from an occupied Bi 6s band to hole polaron accommodati ng band state. Another anomaly at 225 K is believed to occur from the hoppi ng of a hole between a Bi 6s band and the Fermi level. (C) 1999 American In stitute of Physics. [S0021-8979(99)05023-9].