Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

Abstract

In this research, nanocrystalline lithium ferrite (Li 0.5 Fe 2.5 O 4 ) was synthesized using the solution combustion approach with using glycine as fuel and a chelating agent at various Red / Ox ratios ("glycine to nitrate" ratio G / N = 0.4, 0.6, 0.8, 1.0). According to the data of energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS), the prepared samples correspond in their composition to stoichiometric ferrite Li 0.5 Fe 2.5 O 4 within the error of the determination methods used. The results of powder X-ray diffractometry (PXRD) confirmed the formation of α-Li 0.5 Fe 2.5 O 4 at G / N ratio of 0.8 and 1.0 and the presence of β-Li 0.5 Fe 2.5 O 4 modification in case of deficiency (G / N = 0.4) and stoichiometry (G / N = 0.6) of the chelating agent. It is shown that a change in the Red / Ox composition of reacting solutions affects not only the phase composition of the synthesized lithium ferrite samples, but also the crystallite size, which lies in the range from 22 to 35 nm. Based on the scanning electron microscopy (SEM) data, it was found that Li 0.5 Fe 2.5 O 4 powders had a developed porous microstructure consisting of micron agglomerates. According to the vibration magnetometry data of nanocrystalline lithium ferrite powders, it follows that all synthesized compositions have a pronounced ferrimagnetic behavior, despite the presence of β-modification in some of them. It is shown that by varying the Red / Ox environment and, as a consequence, the phase composition and crystallite size, it is possible to obtain Li 0.5 Fe 2.5 O 4 nanocrystals with magnetic parameters in the following ranges: saturation magnetization (M s ) = 51.6 -61.9 emu / g, residual magnetization (M r ) =14.3 -17.8 emu / g, coercive force (H c ) =109 -135 Oe.

Facile combustion synthesis of TbFeO3 nanocrystals with hexagonal and orthorhombic structure

“…Nanocrystalline terbium orthoferrite was obtained by the glycine-nitrate combustion method using glycine as fuel at different G/N ratios in the initial mixture (G/N = 0.2-1.4) using the technology described in detail in [13,14]. The reaction solution was prepared using nitrates of terbium (Tb(NO 3 ) 3 •6H 2 O) (puris.…”

Synthesis, Structure, and Antimicrobial Performance of NixZn1−xFe2O4 (x = 0, 0.3, 0.7, 1.0) Magnetic Powders toward E. coli, B. cereus, S. citreus, and C. tropicalis

“…Therefore, a several studies have been aimed at developing new methods for obtaining nanostructured ferrites [37]. Among the currently known methods, the methods of hydrothermal treatment [38,39], sonochemical synthesis [40,41], sol-gel synthesis [42,43], the method of solution combustion synthesis (SCS) stand out [44,45]. All methods of "wet chemistry" listed above make it possible to obtain controlled nanostructures in a wide range of functional parameters applicable for a plethora of applications, including the biotechnological field [46].…”

Two-step combustion synthesis of nanocrystalline Zn1-xMnxFe2O4 (0<x<1) spinel ferrites with linear tuning of magnetic parameters

“…In addition, several works have shown the possibility of using nanostructured spinel ferrites as catalysts and photocatalysts [11], for wastewater treatment [12], as antibacterial materials [13]. For the application of this class of compounds in these areas, structural parameters are especially important, among which the size of particles and their size distribution should be singled out separately [14]. In recent years, a large number of methods have been used to obtain ferrite nanopowders of various compositions, including hydrothermal synthesis [15], co-precipitation method [16], solution combustion method [17], sol-gel synthesis [18], and many other methods.…”