Luminescence of the samarium ions doped in the complex oxides with heterovalence substitution

Spectral investigation of luminescence both of cadmium tungstate (CdWO4) and calcium vanadate apatite (Ca5(VO4)3OH) crystals doped with samarium (Sm3+) ions are reported in the paper. Luminescence and excitation spectra of the investigated samples consist of both wide nonstructural spectral bands caused by matrix emission and narrow lines caused by electron transitions in the inner 4fn shell of the Sm3+ ions. The obtained results allow us to make a conclusion about formation of two types of samarium ion centers in both types of the crystal lattices. Taking into account that lines corresponding to these two centers are distinctively (up to 50 cm−1 for the cadmium tungstate crystals) distant, an assumption can be made about a manifestation of two nonequivalent arrangements of impurity ions in the crystal lattice.