Spectroscopic evidence of spinel phase clustering in solid solutionsHg1−xCrxSe (0.03 ≤ x ≤ 0.1)

Abstract

The diluted magnetic semiconductorsHg1−xCrxSe (0.03≤x≤0.1) were prepared by the solid state recrystallization method. The structure microanalysis of theHg1−xCrxSe compounds, performed by using a scanning electron spectrometer, has shown that theHgCr2Se4 spinel-like inclusions are present in the host matrixHg1−xCrxSe and their amount increases when the chromium content grows. ESR studies ofHg1−xCrxSe samples were carried out in the temperature range 4.2–300 K. ESR spectraof the samples with different chromium contents demonstrate the sameg-factorsat room temperature and similar fine structure development with the temperature decrease. Numericalstudies of g-factors, performed by the modified crystal field approach (MCFA), allowed us to reveal thatCr2+/Cr3+ ions in the tetrahedral environment of the solid solutionHg1−xCrxSe cannot lead to the ESR signal. The experimentalg-factor is well reproducedby a numerical g-factor for Cr3+ ions located in the octahedral environment, being specific for theHgCr2Se4 spinel phase. The onset of the ESR fine structure is determined by the trigonal distortions of the(CrSe6)9− octahedral cell. From our study it has been found that the spinel clusters are present in theHg1−xCrxSe solid solution even at low chromium content.