Metal-insulator transition induced by a spin-state transition in TbBaCo2O5+delta (delta=0.5)

Authors
Moritomo, Y Akimoto, T Takeo, M Machida, A Nishibori, E Takata, M Sakata, M Ohoyama, K Nakamura, A
Citation
Y. Moritomo et al., Metal-insulator transition induced by a spin-state transition in TbBaCo2O5+delta (delta=0.5), PHYS REV B, 61(20), 2000, pp. R13325-R13328
Citations number
20
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
61
Issue
20
Year of publication
2000
Pages
R13325 - R13328
Database
ISI
SICI code
0163-1829(20000515)61:20<R13325:MTIBAS>2.0.ZU;2-D
Abstract
Temperature variation of the crystal structure has been investigated for Tb BaCo2O5+delta (delta=0.5), which shows a metal-insulator (MI) transition at T(MI)approximate to 340 K. The compound has an oxygen-deficient perovskite structure, with alternating CoO6 octahedral and CoO5 pyramidal chains alon g the crystallographic b axis. We have found that both the pyramids and oct ahedra are significantly distorted in the insulating phase below T-MI, sugg esting a d(3x2-r2)/d(3y2-r2)-type orbital ordering.