New cadmium and rare earth metal tungstates with the formula Cd0.25RE0.50 0.25WO4 （RE=Nd, Sin, Eu, Gd, D-statistical distrib- uted vacancies in cation sublattice） were synthesized by the solid-state reaction between...New cadmium and rare earth metal tungstates with the formula Cd0.25RE0.50 0.25WO4 （RE=Nd, Sin, Eu, Gd, D-statistical distrib- uted vacancies in cation sublattice） were synthesized by the solid-state reaction between CdWO4 and corresponding RE2W209. The obtained phases crystallize in the scheelite type structure. The Cd0.25RE0.5 0.25WO4 compounds were characterized by X-ray diffractometer （XRD）, （DTA-TG）, infrared （IR） and EPR methods.展开更多
Single crystal of Eu3þ-doped cadmium molybdate(Cd0.9268M0.0244Eu0.0488MoO_(4),where M denotes cationic vacancies)has been successfully grown by the Czochralski method in air and under 1 MPa.X-ray diffraction anal...Single crystal of Eu3þ-doped cadmium molybdate(Cd0.9268M0.0244Eu0.0488MoO_(4),where M denotes cationic vacancies)has been successfully grown by the Czochralski method in air and under 1 MPa.X-ray diffraction analysis indicates that as-grown single crystal exhibits tetragonal scheelite-type structure(a=b=5.16188(14)Å;c=11.2080(5)Å;space group I41/a).Eu^(3+) þions do not show long-range order and they are randomly distributed in CdMoO_(4) framework substituting Cd^(2+ )þones.UVevis diffuse reflectance measurements revealed very close optical band gap(Eg)values,i.e.-1.74 eV along[100]and[001]crystallographic directions that are twice smaller than Eg of microcrystalline pure CdMoO_(4) as well as powder Eu3þ-doped single crystal.Magnetic and electrical studies of Eu3þ-doped cadmium molybdate single crystal showed a paramagnetic and n-type semiconducting behaviour with the metal-insulator transition above 350 K along both crystallographic directions.Dielectric results analysis using the Cole-Cole fit function revealed that the dipole relaxation process has different time scale depending on the crystallographic direction and exhibits Arrhenius temperature dependence for both studied directions.This fact is accompanied by the colossal dielectric permittivity withεr>8,103.The above results are considered in the framework of narrow europium multiplets of energy comparable to thermal energy.展开更多
文摘New cadmium and rare earth metal tungstates with the formula Cd0.25RE0.50 0.25WO4 （RE=Nd, Sin, Eu, Gd, D-statistical distrib- uted vacancies in cation sublattice） were synthesized by the solid-state reaction between CdWO4 and corresponding RE2W209. The obtained phases crystallize in the scheelite type structure. The Cd0.25RE0.5 0.25WO4 compounds were characterized by X-ray diffractometer （XRD）, （DTA-TG）, infrared （IR） and EPR methods.
基金the Institute of Physics(University of Silesia)for providing practical and technical assistance.
文摘Single crystal of Eu3þ-doped cadmium molybdate(Cd0.9268M0.0244Eu0.0488MoO_(4),where M denotes cationic vacancies)has been successfully grown by the Czochralski method in air and under 1 MPa.X-ray diffraction analysis indicates that as-grown single crystal exhibits tetragonal scheelite-type structure(a=b=5.16188(14)Å;c=11.2080(5)Å;space group I41/a).Eu^(3+) þions do not show long-range order and they are randomly distributed in CdMoO_(4) framework substituting Cd^(2+ )þones.UVevis diffuse reflectance measurements revealed very close optical band gap(Eg)values,i.e.-1.74 eV along[100]and[001]crystallographic directions that are twice smaller than Eg of microcrystalline pure CdMoO_(4) as well as powder Eu3þ-doped single crystal.Magnetic and electrical studies of Eu3þ-doped cadmium molybdate single crystal showed a paramagnetic and n-type semiconducting behaviour with the metal-insulator transition above 350 K along both crystallographic directions.Dielectric results analysis using the Cole-Cole fit function revealed that the dipole relaxation process has different time scale depending on the crystallographic direction and exhibits Arrhenius temperature dependence for both studied directions.This fact is accompanied by the colossal dielectric permittivity withεr>8,103.The above results are considered in the framework of narrow europium multiplets of energy comparable to thermal energy.
