Negative dielectric behavior in tetragonal La0.8Co0.2-xEuxTiO3 (x=0.01-0.04) nanorods

The La0.8Co0.2-xEuxTiO3 (x = 0.01, 0.02, 0.03 & 0.04)/LCET nanorods are synthesized via the hydrothermal technique. The tetragonal phases are detected by the X-ray diffraction (XRD) patterns. In addition, few minor orthorhombic alpha-Eu2TiO3 phases are noticed. The field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) pictures show the sequential evolution of nanorods as a function of Eucontent. The x = 0.04 content exhibits the complete formation of nanorods. The wide optical band gap (E-g) of x = 0.01, 0.03 & 0.04 contents is increased from 3.621 to 3.973 eV while the narrow E-g similar to 2.293 eV is observed for x = 0.02 content. Interestingly, the high negative dielectric constant (epsilon') and dielectric loss (epsilon '') values of - 78.68 and - 202.84, respectively, are recorded at 8 MHz frequency, for x = 0.04 content. This kind of metamaterials like behavior can offer the high frequency microwave device applications. Furthermore, the frequency dependency of dielectric constant, dielectric loss, ac-electrical conductivity, dielectric modulus, and impedance parameters is described.