Investigation of the dielectric and optoelectronic properties of Nd3+ -substituted bismuth ferrite ceramics in THz/far-infrared region

The real part of the dielectric permittivity of bulk ceramic ferroelectric of composition Bi1-xNdxFeO3 (x = 0, 0.15, 0.2), synthesized by solid-state route, was characterized in the frequency range 0.1-3.5 THz using time-domain Tera-Hertz spectroscopy, and the effect of Nd3+ concentration on the Terahertz (THz) properties of polycrystalline BiFeO3 (BFO) was investigated and is being reported for the first time. A partial transformation in the rhombohedral structural symmetry of BiFeO3 was noticed with increasing Nd3+ % concentration. With increasing Nd3+ concentration, a gradual increase in the THz signal strength has been observed indicating a reduction in losses. For the first time, the refractive index and absorption coefficients of Bi1-xNdxFeO3 (x = 0.0, 0.15, 0.20) samples were measured in the THz reflection mode, and the sample with higher Nd concentration was found to be more stable in terms of refractive index and absorption coefficient. The sample with x = 0.2 has the highest dielectric value (similar to 4.5) at 3.5 THz radiation, which could have potential for THz applications. The detected temporal and spectral THz profiles of Bi1-xNdxFeO3 (x = 0, 0.15, 0.2) bulk ceramic have shown exceptional stability in the frequency range studied.