Raman and Mossbauer Spectroscopy and X-ray Diffractometry Studies on Quenched Copper–Ferri–Aluminates

Autor: N.H. Vasoya, C. R. Kathad, Sonal V. Dulera, Kunal B. Modi, P. Y. Raval, V. K. Lakhani, S. J. Shah, Mansi V. Popat, Prafulla K. Jha, K. B. Zankat, K. G. Saija, Usha Chandra, T. K. Pathak
Rok vydání: 2015
Předmět:
Zdroj: Inorganic Chemistry. 54:1543-1555
ISSN: 1520-510X
0020-1669
DOI: 10.1021/ic502497a
Popis: Four spinel ferrite compositions of the CuAl(x)Fe(2-x)O4, x = 0.0, 0.2, 0.4, 0.6, system prepared by usual double-sintering ceramic route and quenched (rapid thermal cooling) from final sintering temperature (1373 K) to liquid nitrogen temperature (80 K) were investigated by employing X-ray powder diffractometry, (57)Fe Mossbauer spectroscopy, and micro-Raman spectroscopy at 300 K. The Raman spectra collected in the wavenumber range of 100-1000 cm(-1) were analyzed in a systematic manner and showed five predicted modes for the spinel structure and splitting of A1g Raman mode into two/three energy values, attributed to peaks belonging to each ion (Cu(2+), Fe(3+), and Al(3+)) in the tetrahedral positions. The suppression of lower-frequency peaks was explained on the basis of weakening in magnetic coupling and reduction in ferrimagnetic behavior as well as increase in stress induced by square bond formation on Al(3+) substitution. The enhancement in intensity, random variation of line width, and blue shift for highest frequency peak corresponding to A1g mode were observed. The ferric ion (Fe(3+)) concentration for different compositions determined from Raman spectral analysis agrees well with that deduced by means of X-ray diffraction line-intensity calculations and Mossbauer spectral analysis. An attempt was made to determine elastic and thermodynamic properties from Raman spectral analysis and elastic constants from cation distribution.
Databáze: OpenAIRE
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