The ordered K{sub 2}NiF{sub 4}-type structure of mixed crystals La{sub 2{minus}x}Sr{sub x}Li{sub 1/2}Co{sub 1/2}O{sub 4} (x < 0.5) and the electronic properties of the constituting Co{sup III} and Co{sup IV} ions
- Philips Univ., Marburg (Germany). Fachbereich Chemie und Zentrum fuer Materialwissenschaften
- Freie Univ. Berlin, Berlin-Dahlem (Germany). Inst. fuer Experimental Physik
- Univ. of Groningen (Netherlands)
Solids of the composition La{sub 2{minus}x}Sr{sub x}Li{sub 1/2}Co{sub 1/2}O{sub 4} (x = 0, x {approx_equal} 0.2) crystallize in a superstructure of the K{sub 2}NiF{sub 4} lattice with a doubled unit cell in the (001) plane (space group Ammm; a = b = {radical}2a{sub 0}), caused by cation ordering between lithium and cobalt on the octahedral sites. The electronic structure of the Co{sup III}O{sub 6} and Co{sup IV}O{sub 6} polyhedra, which lie isolated in the lattice, were studied by various spectroscopic techniques (XANES, EPR, optical). The groundstates are low-spin in both cases (t{sub 2g}{sup 6} and t{sub 2g}{sup 5}, respectively), the ligand field parameters of Co{sup III} being close to those characterizing the high-spin/low-spin crossover.
- OSTI ID:
- 679256
- Journal Information:
- Journal of Solid State Chemistry, Vol. 146, Issue 1; Other Information: PBD: Aug 1999
- Country of Publication:
- United States
- Language:
- English
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