Structural, dielectric relaxation and conduction mechanism in Ho-doped Bi0.5Na0.5TiO3 ceramics

Lead-free (Bi1-x Ho-x)(0.5)Na0.5TiO3 (0.00 <= x <= 0.06) i.e., BHNT ferroelectric material was prepared by conventional solid-state reaction method. X-ray diffraction pattern revealed the production of a single-phase compound with a rhombohedral crystal structure for all compositions. The FESEM micrographs demonstrate that adding even a modest amount of Ho2O3 can clearly alter the microstructure. The temperature-dependent dielectric data demonstrates that the depolarization temperature (T-d) decreases, whereas the temperature corresponding to maximum dielectric permittivity (T-m) increases with the rise in Ho content. Impedance spectroscopy and electrical modulus analysis have been used to investigate the electrical conduction process. Using Arrhenius' equation, the activation energy is calculated as a function of the temperature for all the samples as a function of temperature. It has been predicted that the addition of Ho2O3 would compensate the volatilization of Bi2O3 and/or Na2CO3 due to the increase in activation energy. These results demonstrate that BHNT ceramic is a strong competitor as a sustainable and multipurpose material.