Response of La0.8Sr0.2CoO3-d to perturbations on the CoO3 sublattice
Sprache des Titels:
Englisch
Original Kurzfassung:
Emission and transmission Mössbauer studies of La0.8Sr0.2CoO3-d perovskites doped with 0.02
stoichiometric units of oxygen vacancy or 2.5% iron corroborate the occurrence of electronic phase separation
in these systems. The effect of the small perturbation of the CoO3 sublattice with either iron ions or oxygen vacancies on the bulk magnetization as well as on the Mössbauer spectra is in good agreement with the double exchange based cluster model. The magnetoresistance does not show any peak near the Curie temperature, but reaches -84% in a field of 7.5 T at T = 8 K. Below TC = 180 K the Mössbauer spectra distinctly include the contribution from paramagnetic and ferromagnetic regions, providing direct evidence for phase separation. No contribution to the spectra from Fe4+ ions can be observed, which is an unambiguous evidence that at low concentration iron (either directly doped or formed from 57Co by nuclear decay) is accommodated in the cobaltate lattice as Fe3+ ion.
Sprache der Kurzfassung:
Deutsch
Englische Kurzfassung:
Emission and transmission Mössbauer studies of La0.8Sr0.2CoO3-d perovskites doped with 0.02
stoichiometric units of oxygen vacancy or 2.5% iron corroborate the occurrence of electronic phase separation
in these systems. The effect of the small perturbation of the CoO3 sublattice with either iron ions or oxygen vacancies on the bulk magnetization as well as on the Mössbauer spectra is in good agreement with the double exchange based cluster model. The magnetoresistance does not show any peak near the Curie temperature, but reaches -84% in a field of 7.5 T at T = 8 K. Below TC = 180 K the Mössbauer spectra distinctly include the contribution from paramagnetic and ferromagnetic regions, providing direct evidence for phase separation. No contribution to the spectra from Fe4+ ions can be observed, which is an unambiguous evidence that at low concentration iron (either directly doped or formed from 57Co by nuclear decay) is accommodated in the cobaltate lattice as Fe3+ ion.
Journal:
The European Physical Journal B: Condensed Matter and Complex Systems
Volume:
57
Seitenreferenz:
257 - 263
Erscheinungsjahr:
2007
ISSN:
1434-6036
Anzahl der Seiten:
7
Notiz zur Publikation:
Response of La0.8Sr0.2CoO3-d to perturbations on the CoO3 sublattice
Z. Németh, Z. Homonnay, F. Árva, Z. Klencsár, E. Kuzmann, A. Vértes, J. Hakl,
S. Mészáros, K. Vad, P. F. de Châtel, G. Gritzner, Y. Aoki, H. Konno and J. M. Grčneche
Eur. Phys. J. B 57 (2007) 257 – 263
Forschungs-