Oxygen isotopic effect on the IR reflectivity spectra of a La2NiO4.14 single crystal

Benoit Rousseau (1) , Jean-Marc. Bassat (2) , Annie Blin (1) , Marcelo Silva de Oliveira (3) , Philippe Odier (3) , Christophe Marin (4) , Patrick Simon (1)

1 CRMHT - Centre de recherches sur les matériaux à haute température
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 Laboratoire de Cristallographie
4 IMAPEC - Instrumentation, Material and Correlated Electrons Physics

Infrared reflectivity spectra measurements have been realised at T=300 K on the oxygen–isotope exchanged single crystals (16O and 18O) of La2NiO4+δ with δ=0.14. One of the main results lies on transfer of the spectral weight from the mid-infrared spectral range to the far-infrared range upon 18O substitution. This striking effect is studied in the framework of the harmonic oscillator concept by simulating the experimental data with a dielectric function model based on the generalisation of the Lyddane–Sachs–Teller relationship. ..

Mots clés: Infrared spectroscopy; La2NiO4+δ; Single crystal; Isotopic exchange; Electron–phonon coupling; Double damping Drude model

Domaines: Matériaux

Benoit Rousseau, Jean-Marc. Bassat, Annie Blin, Marcelo Silva de Oliveira, Philippe Odier, et al.. Oxygen isotopic effect on the IR reflectivity spectra of a La2NiO4.14 single crystal. Solid State Sciences, 2004, 6 (10), pp.1131-1137. ⟨10.1016/j.solidstatesciences.2004.06.002⟩. ⟨hal-00162854⟩