Monitoring Time-Progression of Structural, Magnetic Properties of Ni Nano Ferrite During Synthesis

Verma R and Kane SN*

Received: June 09, 2020;   Published: July 07, 2020

DOI: 10.32474/MAMS.2020.03.000155

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Abstract

We present time-progression of structural, magnetic properties of NiFe₂O₄ nano ferrite during its synthesis via sol-gel auto combustion technique, monitored by x-ray diffraction XRD, and magnetic measurements. XRD patterns of the samples collected between 18-52 minutes shows the formation of the nano spinel phase (grain diameter: 15.4 nm-28.6 nm), presence of a-Fe2O₃phase was also detected. Samples collected between 8-14 minutes show the amorphous nature of the samples. Time-progression studies show: a) sample taken after 20 minutes shows a sharp decrease of specific surface area (range between 39.01 m²/g to 72.73 m²/g), b) non-equilibrium cationic distribution for samples taken between 16-20 minutes with a continuous increase of Fe³⁺ ions population on B-site with simultaneous decrease of Ni²⁺ population, c) for samples taken after 22, 52 minutes, cationic distribution is close to its ideal value of (Fe³⁺) [Ni²⁺Fe³⁺], d) alteration of a degree of inversion (d), oxygen parameter (u), modification of A-O-B, A-O-A, B-O-B super-exchange interactions, e) ferrimagnetically aligned core, and spin disorder on the surface with a thickness between 1.9 nm to 3.6 nm, reducing the saturation magnetization (ranging between 11.7 - 25.5 Am²/kg), as compared to bulk Ni ferrite (55 Am²/kg), f) low squareness ratio values (0.15-0.22) shows the presence of multi-domain nanoparticles, with coercivity between 111-157 Oe.

Keywords: Time-evolution of properties; Sol-gel auto combustion synthesis; XRD; Nano Ni ferrite; Cationic distribution; Magnetic properties

Abstract| Introduction| Experimental Details| Results and Discussion| Summary| Acknowledgments| Conflicts of Interest| Author Contributions| References|