Structural and magnetic investigations of Fe2O3–TeO2 glasses

Abstract A series of tellurite glasses containing Fe 2 O 3 with the nominal composition x (Fe 2 O 3 )–(1− x )(TeO 2 ), where x = 0.05, 0.10, 0.15, and 0.20, have been synthesized and investigated using X-ray photoelectron spectroscopy (XPS) and magnetization techniques. The Te 3d core level spectra for all glass samples show symmetrical peaks at essentially the same binding energies as measured for TeO 2 indicating that the chemical environment of the Te atoms in these glasses does not vary significantly with the addition of Fe 2 O 3 . Furthermore, the full-width at half-maximum (FWHM) of each peak does not vary with increasing Fe 2 O 3 content which suggests that the Te ions exist in a single configuration, namely TeO 4 trigonal bipyramid (tbp). The O 1s spectra are narrow and symmetric for all compositions such that oxygen atoms in the Te–O–Te, Fe–O–Fe and Te–O–Fe configurations must have similar binding energies. The analysis of the Fe 3p spectra indicates the presence of Fe 3+ ions only, which is consistent with the valence state of the Fe ions determined from magnetic susceptibility measurements.