Spectral investigations of Cu2+ doped beta-barium borate nanopowder by the co-precipitation method

A Cu2+ doped beta-barium borate nanopowder has been synthesized using the co-precipitation method. The average crystallite size of the present system is evaluated at 68 nm and the lattice cell parameters are calculated from x-ray diffraction data. Optical absorption spectral data reveal that the Cu2+ ions are in a tetragonally distorted octahedral site in the host lattice. Direct, indirect and Urbach energies are calculated with the absorption edge technique. Electron paramagnetic resonance results confirm that the Cu2+ ions enter a tetragonally elongated octahedral site at room temperature. The crystal field and spin-Hamiltonian parameters are also evaluated. Fourier transform infrared spectroscopy confirms the vibrational bands of Ba–O and B–O in the system.