Impact of Cr <sup>3+</sup> substitution on the nephelauxetic ratio and Racah parameter of Cr-Mn-Zn nanoferrites
M.A. Abdo, M.S. Sadeq
Abstract
Abstract For the first time, we present the ligand field splitting (10Dq) nephelauxetic ratio ( β ), Racah parameter (B) and stability of Cr 3+ within Mn–Zn nanoferrite which synthesized using the citrate route. These parameters were determined via optical absorption spectra. The obtained bands in the significance range of optical absorption spectra are wide as well as asymmetric; therefore the deconvolution process becomes a necessary task. The values of 10Dq and B have been estimated from the produced bands. The values of 10 Dq are observed to increase from 16366.61 to 16447.37 cm −1 whereas, B values are observed to decrease from 829.81 to 760.80 cm −1 with additional Cr 3+ substitution. The increasing 10Dq and decreasing B values, evidence for bonds between Cr 3+ ions with their environments became a further covalent (less ionic). Moreover, the values of β are observed to decrease for further Cr 3+ substitution. This decrease of β produces less stability between Cr 3+ and its ligand. Furthermore, Dq / B values declare that Cr 3+ centers are in the low-field sites by a slight tendency towards the high-field sites with further Cr/Fe substitution process. Therefore, it was suggested that Cr 3+ substituted Mn–Zn nanoferrites are excellent candidates for diverse optical applications such as a tunable laser.