The labile magnetic structure of JT copper and nickel complexes in the layered oxides

✍ Scribed by Yu.V. Yablokov; T.A. Ivanova

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 177 KB
• Volume: 190-192
• Category: Article
• ISSN: 0010-8545
• DOI: 10.1016/s0010-8545(99)00173-3

✦ Synopsis

The structure and dynamics of magnetic centers and magnetic structures in oxides of A 2 BO 4 type are considered. The local and cooperative Jahn -Teller effect and the lattice perturbations are shown to determine the character of distortions of MeO 6 complexes (Me =Cu 2 + , Ni 3 + ) in LaSrAl 1 -x Me x O 4 and in La 2 -x Sr x CuO 4 . The opposite character of the JT effect in MeO 6 centers with copper (3d 9 ) and low spin nickel (3d 7 ) is demonstrated. The phenomenon of the chemical phase separation was observed in LaSrAl 1 -x Me x O 4 . The single CuO 6

-centers in the Al-phase of LaSrAl 1 -x Me x O 4 with a hole delocalized at four plane oxygens are suggested. The transformation of such centers into the relatively large magnetic centers (magnetic Jahn-Teller polarons) in the Cu-phase of LaSrAl 1 -x Me x O 4 was investigated. The active magnetic centers and labile magnetic structures were discovered in the nonequilibrium state of magnetic system La 2 -x Sr x CuO 4 with a very low content of Sr 2 + ions.