Low frequency noise characteristics of BaTiO3-NiFe2O4 composites at phase transition

In this work we present detailed investigation of low frequency noise characteristics of BaTiO₃-NiFe₂O₄ ceramic composites of different percentage of NiFe₂O₄. At the particular temperatures (that gets under the broad maximum of dielectric permittivity observed around 300 K) very intensive few separate peaks of random telegraph noise signal were observed. It shows that phase transition in the investigated materials goes through separate stages instead of the smeared out one. Characteristic times of the physical processes during the phase transition are close to one millisecond, and activation energy is around (0,34-0,49) eV.