J. Phys. Colloques
Volume 47, Numéro C8, Décembre 1986EXAFS and Near Edge Structure IV
|Page(s)||C8-733 - C8-735|
J. Phys. Colloques 47 (1986) C8-733-C8-735
INVESTIGATION OF THE DOUBLE-PHASE TRANSITION OF Tm3Fe5O12, BY EXAFS SPECTROSCOPYH. BEUTHIEN1, D.v. AHLFTEN1, W. GIRNUS1, A. TORKLER1, W. GUNSSER1 et W. NIEMANN2
1 Institute of Physical Chemistry, University of Hamburg, Bundestrasse 45, D-2000 Hamburg 13, F.R.G.
2 Haldor Topsoe Research Laboratories, DK-2800 Lyngby
Coprecipitated Thulium-iron hydroxides with garnet stoichiometry (TmIG) have been investigated at several annealing temperatures (from 333 K to 1453 K) using differential thermal analysis (DTA), x-ray diffraction (XRD) and EXAFS at the LIII edge of Tm. Two phase transitions at 1043 K and 1091 K are observed by DTA. XRD proves that the crystallization of TmIG is completed at 1091 K. The analysis of the nearest neighbour shell of the EXAFS data shows the presence of three temperature regions separated by the two phase transitions. The different oxide geometries in these regions are elucidated by EXAFS fits.