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Phonon Activity upon Reducing ARuO 3–δ (A = Ca, Sr)
Author(s) -
de la Cruz F.P.,
Massa N.E.,
Nassif V.M.,
Cuffini S.L.,
Carbonio R.E.,
Salva H.
Publication year - 2000
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200007)220:1<603::aid-pssb603>3.0.co;2-4
Subject(s) - deoxygenation , phonon , spectral line , infrared , argon , condensed matter physics , metal , infrared spectroscopy , conductivity , materials science , chemistry , analytical chemistry (journal) , atomic physics , physics , optics , biochemistry , organic chemistry , astronomy , metallurgy , catalysis , chromatography
We present infrared reflectivity and transmission spectra from 30 to 25000 cm —1 of the perovskites CaRuO 3— δ and SrRuO 3— δ annealed in argon atmosphere and measured at room temperature and 77 K. The structural and physical consequences upon deoxygenation of CaRuO 3— δ and SrRuO 3— δ are found in the infrared spectra as a decrease of the plasma frequency, implying fewer effective carriers, and the appearance of phonon bands at 337, 873, and 1436 cm —1 . This allows us to infer that deoxygenation mechanisms generate metal–insulator transitions and perhaps spin reordering. Comparing with the data of untreated CaRuO 3 and SrRuO 3 samples, the influence of the lattice on the optical conductivity became evident. Our overall results suggest that a polaronic environment may provide for the lower energy extra anomalies in the electrodynamic quantities as recently established by Ahn et al. (Phys. Rev. Lett. 82 , 5321 (1999)).