Dielectric and Thermal Behavior of Al-Doped Cobalt Titanate Nanoparticles

The Al_xCo_1-xTiO_3+δ (x = 0.2, 0.4, 0.6 & 0.8) (ACTO) nanoparticles are synthesized via hydrothermal method at low operating temperature of 423 K/8 h. The diiffraction patterns confirm the tetragonal phases of ACTO along with the secondary phases (*Co₃O₄). The morphology shows the homogeneous distribution of nanoparticles. In addition, for x = 0.2–0.4, a = b & c values are found to be decreasing from 0.3776 to 0.3771 nm & 0.8887–0.8878 nm, respectively, while for x = 0.6–0.8, the same values are found to be decreasing from 0.3780 to 0.3778 nm & 0.8881–0.8879 nm, respectively. The M–H curves provide the pure paramagnetic nature for x = 0.6 & 0.8 while the weak ferromagnetic nature for x = 0.2 & 0.4. At 8 MHz, the ɛ′ value of x = 0.2 (high cobalt content) shows the stabilized ɛ′ of ≈32.5 and the ɛ″ values of ACTO are changing from ≈1.6–10.6. Therefore, the x = 0.2 shows the high ɛ′ & ɛ″ suitable for high frequency dielectric absorber applications. The exponent “n” values determined using power law fit are noted to be increasing from 0.512 to 0.852 for x = 0.2–0.6 while the same is decreased to 0.664 for x = 0.8. All the “n” values are less than one and shows that the polaron hopping is slower than site relaxation. The mass loss, decomposition of various ingredient species, and other transition temperatures are evaluated by thermal study.