DPG Phi
Verhandlungen
Verhandlungen
DPG

Berlin 2005 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

TT: Tiefe Temperaturen

TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique

TT 16.76: Poster

Saturday, March 5, 2005, 11:00–16:30, Poster TU C

Low temperature mixed spin state of Co3+ in LaCoO3 evidenced from local lattice distortions — •V. Gnezdilov1, P. Lemmens2,3, Yu.G. Pashkevich4, K.-Y. Choi5, S. Shiry aev6, G. Bychkov6, and S. Barilo61B.I. Verkin Inst. for Low Temp. Physics NASU, 61164 Kharkov, Ukraine — 2Inst. for Physics of Condensed Matter, TU Braunschweig, D-38106 Braunschweig, Germany — 3MPI-FKF, D-70569 Stuttgart, Germany — 4A.A. Galkin Donetsk Phystech NASU, 83114 Donetsk, Ukraine — 5Inst. for Materials Research, Tohoku University, Sendai 980-8577, Japan — 6Inst. of Physics of Solids & Semiconductors, Academy of Sciences, 220072 Minsk, Belarus

Single- and multi-phonon excitations of the single crystalline LaCoO3 were studied using Raman spectroscopy in the temperature region of 5 K - 300 K. First-order Raman spectra show a larger number of phonon modes than allowed for the rhombohedral (D3d6) structure. Additional phonon modes are interpreted in terms of activated modes due to local lattice distortions arising from the Jahn-Teller (JT) activity of the intermediate-spin (IS) state of Co3+ ions. The temperature dependence of the breathing - and stretching-type phonon modes on cooling suggests the presence of Co3+ ions in the intermediate spin state, even at lowest temperatures. The anomalous temperature dependence of the second-order phonon excitations spectra is in accordance with the Franck-Condon mechanism that is characteristic for a JT orbital order.

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2005 > Berlin