Evidence of relaxor freezing in Pb(Mg1/3Nb2/3)O3/BiFeO3 ceramics

The Vogel–Fulcher (V–F) relation has long been adopted to extract the freezing temperature ( T f ) from a dielectric constant–temperature plot. It has been shown that the V–F relation in the relaxation time ( τ max ) scale can be used for a more direct evaluation of T f rather than ω ( T max ) . But in our opinion, neither τ max nor ω ( T max ) gives direct evidence of freezing. Hence, in this letter, we have tried to give direct evidence for relaxor freezing and direct evaluation of T f for a relaxor system [ Pb(Mg1/3Nb2/3)O3 with 20 mol% BiFeO3] using differential scanning calorimetric and pyroelectric measurements.