Raman study of crystal-field excitations inNd1.85Ce0.15

Low-temperature specific heat ofNd2−xCexCuOHiền1, Duijn2, Colpa3 et al. 1998Phys. Rev. B152131View full textAdd to dashboardCite

“…Furthermore, we recall Jandl et al, 18 who proposed the existence of three inequivalent Nd sites to explain the spectra observed in their Raman-scattering experiments on singlecrystalline Nd 1.85 Ce 0.15 CuO 4Ϫy .…”

“…As can be expected from these considerations, we failed to fit the zero-field data as long as we based the calculations on the same model-with only one single type of Nd ions-as applied for the undoped compound, using any of the CEF-parameter sets proposed for the doped compound in the literature. 9,10,18,31 We have also attempted to describe the experimental data by a phenomenological treatment based on a Gaussian distribution of the molecular field without taking into account the Nd-Nd interaction. By adjusting the parameters for the Gaussian molecular-field distribution, we could simultaneously reproduce-albeit not very satisfactorily-the data measured in zero field as well as at 8 T applied in the ab plane, but failed to fit the data obtained at other fields.…”

“…The fitting procedure applied was based on the three inequivalent types of Nd ions, I, II, and III, with the corresponding weights wϭ0.37, 0.46, and 0.17, respectively, and the corresponding CEF-parameter sets proposed by Jandl et al 18 Proceeding along the same lines as for the undoped compounds, we derived from the zero-field specific-heat data values of the fitting parameters B mol Nd-Cu and n RR dif for each of the three inequivalent types of Nd ions. Figure 7 shows the best fit we found.…”

“…8-14͒ and Raman scattering. [15][16][17][18] While consistency in the energy-level schemes has been achieved, there is a large divergence in the CEF-parameter sets proposed among the different groups of authors to interpret these energy-level schemes.…”

Infrared optical properties ofPr2CuO4

“…19 In fact, due to the sigTypeset by REVT E X nificant exchange interactions between the Pr ions which are mediated through the copper-oxygen layers, there is a Pr contribution to the susceptibility 12 below ≈ 200 K. The optical properties of Nd 2 CuO 4 have been investigated in ceramics and single crystals. 20,21,22,23,24,25,26,27 Single crystals of Pr 2 CuO 4 have been studied at either room temperature 28,29,30,31 or at low temperature 11,32 (≈ 10 K), but there has been no detailed investigation of the temperature dependence of the optical properties of this material. Furthermore, there is some disagreement in the literature with respect to the vibrational parameters of the E u modes.…”