Infrared transmission study of crystal-field excitations in Al- and Sr-dopedPr1+xBa2−x

Abstract

Absorption bands corresponding to the crystal-field excitations in Pr 1.05 Ba 1.88 Cu 2.39 Al 0.34 O 6ϩy and Pr 0.93 Ba 1.93 Sr 0.13 Mg 0.05 Cu 2.74 O 6ϩy ͑where yϳ0) have been observed by Raman scattering and infrared transmission spectroscopy. These excitations are assigned to transitions occurring from the two lowest-energy levels of the 3 H 4 multiplet to the excited multiplets 3 H 5 , 3 H 6 , 3 F 2 , and 3 F 3 of Pr 3ϩ ions located in their D 4h -symmetry sites. The spectra exhibit additional bands consistent with the presence of Pr 3ϩ ions in the C 4v -symmetry Ba sites, as well as various defects associated with disorder. This analysis confirms that the phenomenological crystal-field parameters follow the trends reported in NdBa 2 Cu 3 O 6 and SmBa 2 Cu 3 O 6 . A spectral splitting of the ⌫ 5 levels is observed at low temperature and indicates Pr-Cu exchange interaction. Al doping results in the expected inversion of the ⌫ 5 -⌫ 1 symmetry sequence of the quasitriplet ground state, in accordance with the magnetic-susceptibility anisotropy measurements.

Study of crystal-field excitations and Raman active phonons in o-DyMnO3

“…The infrared transmission technique has been used successfully for the study of rare-earth crystal-field (CF) excitations in strongly correlated electron systems such as manganites and high temperature superconductors [11][12][13]. The CF excitation evolutions as a function of temperature and magnetic field provide interesting informations concerning the electronic and the magnetic properties as well as surrounding ligands and local inhomogeneities.…”

Study of crystal-field excitations and infrared active phonons in TbMnO3

“…The IR transmission spectroscopy has been used successfully for the study of rare-earth crystal-field (CF) excitations in strongly correlated electron systems [21][22][23][24][25]. The far IR optical spectroscopy is also a powerful tool to investigate the driving force of the interplay of charge, spin, and lattice degrees of freedom [26][27][28].…”

Study of crystal-field excitations and infrared active phonons in the multiferroic hexagonal DyMnO3

“…In strongly correlated electron systems such as manganites and high temperature superconductors, the infrared transmission technique has been used successfully for the study of rare-earth crystal-field (CF) excitations [16][17][18]. The CF excitation evolutions as a function of temperature and magnetic field provide interesting information concerning the electronic and the magnetic properties as well as surrounding ligands and local inhomogeneities.…”