Spectroscopic evidence of spinel phase clustering in solid solutions Hg(1-x)Cr(x)Se (0.03 ≤ x ≤ 0.1)
K Lamonova1, I Ivanchenko, S Orel
1A A Galkin Donetsk Institute for Physics and Engineering of NASU, 83114, Donetsk, Ukraine.
Abstract:
The diluted magnetic semiconductors Hg(1-x)Cr(x)Se (0.03≤x≤0.1) were prepared by the solid state recrystallization method. The structure microanalysis of the Hg(1-x)Cr(x)Se compounds, performed by using a scanning electron spectrometer, has shown that the HgCr(2)Se(4) spinel-like inclusions are present in the host matrix Hg(1-x)Cr(x)Se and their amount increases when the chromium content grows. ESR studies of Hg(1-x)Cr(x)Se samples were carried out in the temperature range 4.2-300 K. ESR spectra of the samples with different chromium contents demonstrate the same g-factors at room temperature and similar fine structure development with the temperature decrease. Numerical studies of g-factors, performed by the modified crystal field approach (MCFA), allowed us to reveal that Cr(2+)/Cr(3+) ions in the tetrahedral environment of the solid solution Hg(1-x)Cr(x)Se cannot lead to the ESR signal. The experimental g-factor is well reproduced by a numerical g-factor for Cr(3+) ions located in the octahedral environment, being specific for the HgCr(2)Se(4) spinel phase. The onset of the ESR fine structure is determined by the trigonal distortions of the (CrSe(6))(9-) octahedral cell. From our study it has been found that the spinel clusters are present in the Hg(1-x)Cr(x)Se solid solution even at low chromium content.
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