Preparation and Characterization of Chromium Doped Ni-Cu-Zn Nano Ferrites

Abstract

Chromium doped Ni-Cu-Zn nano ferrites with chemical formula Ni 0.2 Cu 0.2 Zn 0.6 Fe 2-x Cr x O 4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by using sol-gel auto combustion method. The prepared precursors of Chromium substituted Ni-CuZn ferrites were sintered at 500 °C for 4h. Compositional stoichiometry were confirmed from EDAX patterns. The XRD data revealed that the all samples possess a single phase cubic spinel structure. The Lattice constant, X-ray density, hopping lengths and crystallite size determined from XRD data decreases with increase in Cr 3+ concentration. The IR spectra show two major absorption bands, high frequency band ν 1 ≈ 600 cm -1 and low frequency band ν 2 ≈ 450 cm -1 attributed to the stretching vibration of tetrahedral and octahedral sites respectively. The surface morphology of the prepared samples was studied by Scanning Electron Microscopy and Transmission Electron Morphology.

Effect of Cr3+ substitution on magnetic and electrical properties of (Ni0.3Cu0.7) Fe2O4 spinel ferrites

“…25-0283 [25] for checking the phase purity of the samples. The reflections observed in XRD patterns are (220), (311), (222), (400), (333), (440), which belong to a fcc spinel structure having space group Fd3m [26]. The lattice constant of all samples was calculated by using the equation given below,…”

“…Crystallite size decreases with increasing concentration of chromium ions. Table I shows the decreasing trend of crystallite size is attributed to the addition of chromium ions which creates hindrance in the growth grain [26]. Figure 2 shows the graphs of MH-loops for (Ni 0.3 Cu 0.7 )Cr x Fe 2−x O 4 samples.…”

The Green and Efficient One-pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives

“…In recent years, Various methods have been reported for the synthesis of 4H-pyran and its derivatives via threecomponent condensations including the use of various media or catalysts such as hexadecyltrimethylammonium bromide (HTMAB) [10], tetra-methyl ammonium hydroxide [11], sodium selenate (Na2SeO4) [12], PEG1000-DAIL [13], amberlite IRA400 (OH-) [14], tetrabutylammonium bromide (TBAB) [15], trisodium citrate [16], phenylboronic acid (Ph B(OH)2) [17], Potassium phthalimide-N-oxyl (POPINO) [18], starch solution [19], tetrabutylammonium fluoride (TBAF) [20], NH4Al(SO4)2 12H2O (Alum) [21], Nano-kaolin-TiCl4 [22], CuFe2O4.starch [23], Dendrimeric magnetic nanoparticle [24] and ceriavanadia/silica [25]. Some of the previous methods have posed a number of problems such as lengthy procedures, being highly corrosive, using expensive catalysts, volatile solvent, laborious work-up and high energy consumption caused by the high temperature reaction.…”