Existence of internal domains in LixTiy Ni1-x-yO and their effects on dielectric behaviour

The elusive domain structures inside the grains of polycrystalline LixTiyNi1-x-yO (LTNO, with x = 0.05, y = 0.02) were observed by scanning electron microscopy and high-resolution transmission electron microscopy. Impedance spectroscopy (IS) analysis was further explored to explain the behaviour of the charge carriers and dielectric spectra of the LTNO ceramic. An equivalent circuit model has been established to separate domain (D), domain-boundary (DB) and grain boundary (GB) relaxation of LTNO. IS analysis reveals that the domain interior of LTNO is Li modified. The activation energy of D, DB and GB is 0.154 eV, 0.216 eV and 0.423 eV, respectively.