Research On Structure And Magnetism Of CdGd₂(WO₄)_4-δ Single Crystal

The single crystal CdGd2(Wo4)4-δwas studied in the paper. The crystal was grown by Czochralski method. The conditions were as follows: pulling rate 0.84mm/h, rotating rate 40rpm, temperature gradient 46.0~47.00C/cm, cooling rate 320C/h. X-ray diffraction (XRD) determined that the crystal structure is tetragonal scheelite with lattice parameters a=b=0.5203nm and c=11.359nm. The crystal density is ρ= 7.668 g /cm3. The optical transmittance of the single crystal was measured from the ultraviolet to the visible range. The energy gap Eg and E g'are 3.78 ev and 3.63ev which correspond to the direct transition and indirect transition, respectively; the energy of phonons taking part in the indirect transition is 0.095 ev. The Raman spectrum has been assigned. The 925,818,777cm-1 vibration is the stretch of the WO4 unit ; the 404 and 328cm-1 vibration is the bending ; the 205 and152 cm-1 vibration is the rotation of cation. Langevin paramagnetism and anisotropy are showed in dependences of quality ratio σto temperature T and σto magnetic field H. Its anisotropy also is showed by Electron Spin Resonance (ESR) experiments. The anisotropy of the crystal relates to the structure. The parallel susceptibility χ+ of crystal to the c-axis is 3.5018 ×10?3 and perpendicular susceptibility χ⊥to the c-axis is 3.4403 ×10?2 at room temperature. ESR experiment was analysed by anisotropy field and g factor . The anisotropy field is 0.070T, g factor square g2 is g有效correspond to different angle is calculated from [g2]. Our experiment analysis result is consistent with theory result.