Ellipsometric Studies of NdMnO 3 Single Crystals

G.J. Babonas a , A. Reza a , R. Szymczak b , M. Baran b , S. Shiryaev c , J. Fink-Finowicki b and H. Szymczak b a Semiconductor Physics Institute, Gostauto 11, 2600 Vilnius, Lithuania b Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland c Institute of Solid State and Semiconductors Physics, NAS, P. Brovka Street, 220072, Minsk, Belarus

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Ellipsometric studies of NdMnO 3 single crystals of orthorhombic symmetry were carried out in the spectral range 0.5 - 5.0eV. Experimental data, which were obtained on the (001) pc -type planes of pseudo-cubic system, were analyzed in the model of biaxial crystal. For the first time, three components ϵ x , ϵ y , ϵ z of the effective dielectric function for manganites of orthorhombic symmetry were determined. From ellipsometric data, the spectra of optical conductivity and loss function were also calculated and considered. The fine structure of the spectra and optical anisotropy was the basis for discussion of the microscopic origin of the optical transitions responsible for the optical features. The electronic excitations due to dipole-forbidden spin-allowed transitions of the d-d-type in Mn-ions, f-f-type in Nd-ions and charge-transfer 2p(O)-3d(Mn) transitions were taken into account. The data for NdMnO 3 were compared with those obtained for other related undoped and doped single crystals of perovskite-type structure, LaMnO 3 , (LaBa)(MnCo)O 3 and (LaCa)CoO 3 .

DOI: 10.12693/APhysPolA.105.197 PACS numbers: 71.20.--b, 78.20.Ci