Unusual enhancement of high-temperature electronic transport in PrBaCo2O6-δ under Ga doping: reasons and consequences.

Solid oxide PrBaCo1.8Ga0.2O6-δ (PBCG) is synthesized using a glycerol-nitrate route. XRD and SEM techniques are utilized in order to confirm the structural and microstructural composition of the attained ceramics. The high-temperature electrical conductivity and thermopower of the sintered PBCG sample are measured in a wide range of external conditions. It is shown that Ga doping results in ∼30% increase of conduction properties. The observed peculiarity is interpreted in terms of a recently proposed electronic transport model. It is argued that the respective enhancement of conductivity originates from the combined increase of polaron hopping frequencies along with a decline of carriers' effective mass in the metallic subsystem of PBCG.