Resumo

GUTIERREZ, M. P. et al. Influencia del método de síntesis en la respuesta de resonancia paramagnética electrónica en manganitas. Superf. vacío [online]. 2005, vol.18, n.1, pp.6-10. ISSN 1665-3521.

The microwave absorption response for polycrystalline samples La0.85Sr0.15MnO3 prepared by two different methods are compared. Two different samples were prepared: one by the traditional ceramic method and the other by means of a sol-gel precursor followed by a sintering process. Measurements were carried out at X Band (9.2 GHz) with a dc magnetic field up to 8000 Gauss, in the 300-80 K temperature range. Electron Paramagnetic/Ferromagnetic resonance (EPR/FMR) spectra of both samples show important differences indicating that the magnetic absorption processes and the phase transition temperatures are sensitive to the local order/disorder induced by the route of preparation. These results are supported by dc resistivity and magnetic susceptibility measurements as a function of the temperature.

Palavras-chave : Electron paramagnetic resonance; Ferromagnetic resonance; Manganites.