ABSTRACT Neel temperature of Pb(Fe1/2Nb1/2)O3 ceramics sintered at 1120°C and quenched to room temperature was revealed to be 25 K higher than that of the same ceramics slowly cooled at… Click to show full abstract
ABSTRACT Neel temperature of Pb(Fe1/2Nb1/2)O3 ceramics sintered at 1120°C and quenched to room temperature was revealed to be 25 K higher than that of the same ceramics slowly cooled at a rate of 50 K/h. A small singlet component, typical for compositionally ordered perovskites, is present in the room-temperature Mossbauer spectrum of the slowly cooled sample. It proves that the quenched sample is more compositionally disordered than the slowly-cooled one. Substantially higher room-temperature resistivity values and positive temperature coefficient of resistivity of the slowly cooled sample are attributed to the formation of the grain-boundary potential barriers due to oxidation during slow cooling.
               
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