Microstructure, magnetic properties of Ho3+ substituted Ni-Cu-Zn spinel ferrites and application for one pot synthesis of dihydropyrimidinones

Abstract

Nanoparticles of Ni-Cu-Zn spinel ferrites with Ho3+ substitution were synthesized through the sol–gel auto combustion route. It is illustrated from thermogravimetric analysisand differential thermal analysiscurve that the decomposition of precursors takes place in the temperature range 350–460 oC. The Energy dispersive spectroscopy confirmed the mixing of the Fe, Ni, Cu, Zn, Ho and oxygen elements in stoichiometry proportion in pure and substituted spinel ferrites with desired stoichiometry. X-ray diffraction pattern confirmed the formation of cubic spinel structure without any impurity phases. Lattice constant, X-ray density increases while average crystallite size decreases with increased Ho3+substitution in Ni-Cu-Zn ferrites. The two strong IR absorption bands observed in the range 565–568 (ν1) and 409–438 (v2) cm−1. The obtained crystallite size lies between of 18 – 26 nm, confirmed from transmission electron microscopy. The microstructures of the calcinated spinel ferrites were evaluated by SEM and TEM. It is observed that the increase in concentration of Ho3+ ions saturation magnetization decreases. Prepared Ho3+ substituted Ni-Cu-Zn spinel ferrites were used as catalyst to synthesize the 3,4-dihydropyrimidin-2(1H)-ones.[copyright information to be updated in production process]