Structural, optoelectronic and ferroelectric behavior of A & B site modified BaTiO3

Abstract

Ferroelectric barium titanate (BT) possesses a high dielectric constant coupled with good thermal stability. Therefore, it is an interesting material for applications such as multilayer ceramic capacitors, piezoelectric and pyroelectric sensors or dynamic random-access memories (DRAM). It is the first discovered ferroelectric perovskite. It has the classic ABX3 (with Ba2+ as A and Ti4+ as B) perovskite structure. There are many studies reported for properties of BT ceramics, some reports are focused to increase its Curie temperature and dielectric constant, and some are focused on increasing its ferroelectric properties. In the present work we have modified the BT ceramics with Ca, V, Cu and Bi, Cu doping. Modified BaTiO3 ceramic Samples Ba(0.9)Ca(0.1)Ti(1-3x)Cu(x)V(2x)O3 (BCTCV)and Ba1-xBixTi1-xCuxO3 (BBC) have been synthesized via Solgel method. The X-ray Diffraction (XRD) of samples were done to confirm its formation. Vibrational modes of the samples are studied and verified by the Raman spectroscopy. The dielectric constant (𝜀) and dielectric loss (𝑡𝑎𝑛𝛿) have been measured for both samples. The variation of dielectric constant and dielectric loss as a function of temperature has been studied. Optical properties of the samples are studied using the diffused reflectance spectroscopy. The ferroelectric nature of the ceramics have been confirmed by P-E hysteresis loop study. FESEM on the samples were done to check the surface morphology of the sample. To have a modified BT ceramic with relatively higher Curie temperature and comparable dielectric constant, can be great aid in many technological advancements. Better PE loop response is also desired for many applications such as storage devices. Rising Tc was confirmed by temperature dependence of the dielectric constants study. This is one of very few examples for rising Tc in the solid solution based on BaTiO3 except for doping of Pb2+ ion.