  In this manuscript, we report room temperature structural, microstructural,
optical, dielectric, and magnetic properties of CuO and Cu0.995La0.005
ceramics, synthesized by solid-state reaction method. La doping in CuO leads to
the evolution of compact and dense microstructure with reduced porosity. Due to
noticeable differences in the ionic radii of, La doping creates vacancy defects
which induce considerable strain in the CuO lattice resulting in a reduction in
the lattice parameters and cell volume. However, both ceramics processes a
similar monoclinic structure with the C2/c space group. Detailed
characterization using XPS, Raman, and FTIR spectroscopy confirmed the
incorporation of the La3+ in CuO lattice. Interestingly, La doping enhances the
dielectric constant by more than three times and results in a reduced leakage
current. The onset of a large dielectric constant is attributed to dense
microstructure and strain/distortion in CuO lattice after La doping.
Additionally, the band-gap of Cu0.995La0.005 ceramics decreases which is
attributed to increased vacancy defect concentration that creates intermediate
dopant energy level within bandgap of CuO matrix. Furthermore, improvement in
magnetic and dielectric properties is also discussed and correlated with the
grain size in La-doped CuO.
