Dynamics of nano-cluster in a new relaxor system: (PbMg1/3Nb2/3O3)/(BiFeO3)

We report the dynamical role of nano-clusters in controlling the physical properties and parameters of a new relaxor complex, (PbMg1/3Nb2/3)O3/(BiFeO3). This complex shows a gradual structural change from cubic to hexagonal crystal system with increasing BiFeO3 content. Transmission electron microscopy (TEM) reveals the presence of scattered nano-clusters for (PbMg1/3Nb2/3)O3 relaxor system which starts assembling for increasing value of BiFeO3. As a consequence of this assembling, a crossover from relaxor to ferroelectric and dielectric peak broadening was observed. Corresponding change in physical parameters such as; Curie–Weiss and Uchino–Nomura parameters i.e., ΔTcm and diffusivity ‘γ’ was also observed. Vogel–Fulcher (V–F) fitting was employed to calculate the activation energy required to activate the dipolar glasses into a dynamical state or to re-establish a polarization fluctuation around an isolated nano-cluster. V–F fitting shows increased activation energy for increasing cluster size. The suppression in polarization value shows the inability of the total dipole moment to reorient on application of electric field with growth/assembling of nano-clusters.

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