Structural transformation and high negative dielectric constant behavior in (1-x) (Al0.2La 0.8 TiO3) + (x) (BiFeO3) (x=0.2-0.8) nanocomposites

The (1-x) (Al0·2La0·8TiO3) + (x) (BiFeO3) nanocomposites were synthesized via low temperature hydrothermal method. The X-ray diffraction (XRD) patterns established the tetragonal phases for x = 0.2 while the cubic phases were detected in case of x = 0.4, 0.6 & 0.8 composites. The surface morphology was analysed using field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The results indicated that there was a clear formation of well-defined spherical grains/particles for x = 0.4 composites. The UV–Visible spectral analysis showed the optical band-gap energy (Eg) increasing from 5.499 to 5.721 eV as a function of ‘x’. In addition, the dielectric properties revealed the negative dielectric constant (ε′) and dielectric loss (ε") parameters between the frequencies 2887 Hz–8 MHz. The data suggested that the ε′ and ε" values were noticed to be −1234 and −248.7, respectively, at 8 MHz. The magnetic hysteresis loop behavior exhibited the paramagnetic nature for x = 0.2–0.8. Moreover, the saturation magnetization (Ms) was determined using the law of approach saturation (LAS) plots. These plots ensured the variation of Ms from 0.0254 ± 0.00132 to 0.194 ± 0.00454 emu/g. © 2020 Elsevier B.V.