New spectroscopic effects of ferroelectric phase transition in Li2Ge7O15crystals doped with 3d3-ions

Abstract In Li2Ge7O15(LGO) crystals doped with Cr3+ and Mn4+ ions the transformation of luminescence spectra in the region of R-lines at ferroelectric phase transition D2h → C2x in LGO was used to determine the point group symmetry and microstructure of 3d3-centers. In experiments on pseudo-Stark splitting of R-lines in external electric field, the phase transition induced polarization of 3d3-ions was observed, the induced dipole moments being directed perpendicular to ferroelectric axis of C2x phase. Key Words: Key words Li2Ge7O15:Cr3- Li2Ge7O15:Mn4+center symmetrycharge compensationdipole momentphase transition