Lead-free Ba(Fe 1=2 Nb 1=2 ÞO 3 /PVDF 0-3 composites were fabricated using melt-mixing technique. X-ray diffraction, scanning electron microscopy, dielectric, impedance, ac conductivity, magnetic force microscopy (MFM) and vibrating sample magnetometer studies were undertaken to characterize the samples. Average crystallite size of the Ba(Fe 1=2 Nb 1=2 ÞO 3 powder, estimated using Williamson-Hall approach, was found to be $ 42 nm. The filler particles of $ 0:5À1 m were found to disperse in the polymer matrix of all the composites. Filler concentration-dependent values of real and imaginary parts of complex permittivity showed increasing trend and were seen to follow Bruggeman and Furukawa equations. The data for ac conductivity exhibited negative temperature coefficient of resistance character of the test materials and were found to obey Jonscher's power law. The correlated barrier hopping model was found to explain satisfactorily the mechanism of charge transport occurring in the system. MFM confirmed the presence of magnetic phases in the composites. Typical magnetization versus applied field curves indicated the possibility of magnetoelectric coupling in the system. Hence, the present composites have shown themselves as potential multifunctional candidate materials for use in high density data storage applications.

No abstract

No abstract