Superparamagnetic Lanthanide La3 Gd3 Nd3 Doped MnZn Ferrite Nanoparticles Effect of Dopant Content

Abstract

Superparamagnetic nanoparticles have the ability to tack themselves in a reasonable magnetic field and have got scientific attention for biomedicine applications. In present work, nanoparticles of Mn0.5Zn0.5RExFe2-xO4 (x = 0, 0.025, 0.050, 0.075, 0.1) ferrites (where RE = La, Gd, Nd) have been prepared using co-precipitation technique. First the sintering temperature has been optimized for Mn0.5Zn0.5Fe2O4 ferrite nanoparticles. From the structural analysis using XRD at three sintering temperatures (973 K, 1173 K,1373 K), a pure spinel phase is observed at 1373 K whereas a secondary phase Fe2O3 has been observed at lower sintering temperatures. The absorption bands at 421 cm-1 - 491 cm-1 and 516 cm-1 - 592 cm-1 in FTIR spectra confirm the formation of spinel ferrite. FE-SEM images have shown the formation of homogenous crystalline nanoparticles with increase in sintering temperature. For further investigation of RE doped Mn-Zn ferrites, the sintering temperature has been taken as 1373 K. Structural investigations have shown cubic spinel phase for all samples. For the three dopants used in Mn-Zn ferrites, the crystallite size, lattice constant, interplanar spacing and packing factor have been determined and found to decrease generally. FTIR spectroscopy has confirmed the occurrence of spinel structure in all the investigated samples. FE-SEM micrographs of all investigated samples show sharp crystalline structures. EDS spectroscopy confirms the presence of constituent elements in all the investigated samples. A cation distribution has been proposed for RE doped manganese-zinc spinel ferrites. Magnetic study has shown paramagnetic and superparamagnetic nature of samples at room temperature. newline