Optical phonons inNd2BaMO5(M=Zn,Cu)

Impact ofCo∕Mncation ordering on phonon anomalies inLa2CoMnTruong1, Laverdière2, Singh3 et al. 2007Phys. Rev. B134171080View full textAdd to dashboardCite

“…[12][13][14][15][16][17] It has been extensively used to study the charge and/or orbital ordering and spin-lattice interactions in manganites and other related compounds. [12][13][14][15][16][17] In these cases, the impact of charge ordering is obvious as it doubles the size of the unit cell and lowers the symmetry of the crystal structure. These structural changes lead to the appearance of new phonon excitation in Raman spectra.…”

Interatomic forces in Pnma, Immm, P4/mbm and I4/mcm phase of R2BaMO5(R= yttrium or lanthanides; M= Ni, Cu or Zn)

“…The reason also discussed by Andres et al [15] for this may be due to the presence of the shielding layer of O2 surrounding the Ba atom. Similarly the interaction between Nd and Zn was found negligible unlike the Immm [6] and P4/mbm [7] [1,10,15]were observed but could not be assigned properly in the experimental studies. However in the present calculation, the infrared active phonons were evaluated and assigned properly but a comparison with the experiment could not be made as the experimentally measured values were not known for the specific modes.…”

“…In I4/mcm structure five stretching force constants for the nearest neighbours Zn-O2, Nd-O2, Nd-O1, Nd-O2, and Ba-O2 and five bending force constants for angles O1-Nd-O2, O2-Zn-O2, O1-Nd-O2, Nd-Nd-O2 and O2-Nd-O2 were used in the calculations. The force constants were evaluated by fitting the observed ten Raman modes [10]. The A 1g,1 and B 2g,1 Raman modes were reassigned on the basis of group theoretical analysis by analyzing the calculated results in the fitting process.…”

Quantum tripling in Tm 3+ doped La 2 BaZnO 5 phosphors for efficiency enhancement of small band gap solar cells

“…5) only the 1 G 4 state is observed and not any other states like the 3 F 2 or the 3 F 3 , indicating that the peak around 1.04 eV is only due to 1 G 4 -3 H 4 emission. The absence of emission from the 3 H 5 can be explained by multi-phonon relaxation to the 3 F 4 state, since the energy difference is 4 times the phonon energy of 650 cm À 1 , based on the phonon energy of Nd 2 BaZnO 5 [10].…”