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A-Site Cation disorder and Size variance effects on the physical properties of multiferroic Bi0.9RE0.1FeO3 Ceramics (RE =Gd3+,Tb3+,Dy3+)

Effect of an internal chemical pressure on structural, optical, magnetic and electrical properties in Bi0.9RE0.1FeO3 Ceramics (RE =Gd3+,Tb3+,Dy3+)has been studied extensively. Some of the highlights are as follows; 1. Coexistence of orthorhombic Bragg reflections along with the R3c phase.(Structural Phase separation revealed from XRD and Raman spectroscopy) 2. Selective softening of phonon mode corresponding to oxygen motion suggests a significant destabilization in the FeO6 octahedra. 3. Three Charge transfer transitions (Fe1 3d\rightarrow Fe2 3d, Op \rightarrow Fed,Op \rightarrow Bip) and a doubly degenerate d-d transition (6A1g \rightarrow 4T2g) have been observed through optical studies. 4. The suppression of spiral spin structure release the macroscopic magnetization so called weak ferromagnetism in RE-BFO samples and expalined by presence of DM interaction 5. Heat flow measurement reveals a decrease in Neel transition temperature (TN) with RE3+-ion substitution endorses the suppression of antiferromagnetic ordering. Present results also provide an 6. A decrease in vacant sites was confirmed from the lower density of states N(Ef) of charge carriers in RE-BFO samples, further it also correlates well with the hopping length (Rmin) and conductivity studies. All the results are well correlated.