Structural and electrical studies of Ba(fenb)0.5O3 based high dielectric constant materials synthesized by conventional and microwave processing techniques

Abstract

There is an increasing interest in the field of dielectric ceramics. The oxide based dielectrics constitute a large portion of the materials which find large-scale technological applications in sensors, actuators, memory devices, high density capacitors etc. Generally, high dielectric constant (εr) is obtained in ferroelectric class of materials. But, for dielectric applications, the ferroelectric classes of materials have following disadvantages: (i) the max. εr is obtained near Curie temperature (Tc) (ii) the Tc is generally far away from RT. These disadvantages forbid the use of the ferroelectric classes of materials in different practical device applications near RT. To some extent, these disadvantages of the ferroelectric classes of materials are minimized by the relaxor ferroelectric materials. But, most of the relaxor ferroelectric materials are enriched with PbO, which is toxic and presently due to the environmental concern, the use of these types of materials is discouraged. Therefore, it is urgent and desirable to find out alternative lead oxide free high εr materials. Considering lead toxicity, there is an urgent need to develop effective lead-free/ low lead content high dielectric constant (HDC) materials, which are environmental friendly in nature. In the present study Ba(Fe0.5Nb0.5)O3/BFN system is chosen as the material of research. Main problems related to the processing of perovskite based oxide ceramics through conventional solid state reaction (CSSR) route are high processing temperature and difficulty in getting better densified product. High dielectric loss in the BFN based ceramics can be utilized for its synthesis by microwave processing technique.