Magnetic Ordering and Enhancement of Magnetization in Zinc-Substituted Copper Ferrite Nanoparticles

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ORIGINAL PAPER

Magnetic Ordering and Enhancement of Magnetization in Zinc-Substituted Copper Ferrite Nanoparticles A. Subha 1 & M. Govindaraj Shalini 1 & Shantinarayan Rout 2 & Subasa C. Sahoo 1 Received: 18 June 2020 / Accepted: 17 July 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract ZnxCu1-xFe2O4 (0.05 ≤ x ≤ 0.85) nanoparticles were synthesized by sol-gel method and were annealed at 500 and 900 °C in air for 3 h. Characterization techniques like XRD, Raman spectroscopy, and vibrating sample magnetometer were used to investigate phase, cation distribution, and magnetic properties. XRD studies showed that all the as-prepared samples are of cubic spinel phase. Tetragonal phase was observed in the samples with x < 0.15 after annealing, whereas all other samples retained cubic phase. Raman spectroscopy showed increase of Zn2+ ions in the tetrahedral site with the increase in Zn2+ concentration in the nanoparticle samples. Cation distribution and magnetic ordering enhanced the magnetization value with increasing x value, and a maximum was observed in the as-prepared and annealed samples. The coercivity decreased with the increase in Zn2+ concentration. The highest magnetization value of 110 emu/g with coercivity of 25 Oe was observed in the present study at 60 K for the sample annealed at 900 °C with x = 0.5. Law of approach to saturation method was adopted to study the magnetic ordering in the nanoparticle samples. The blocking temperature decreased with increase in Zn2+ concentration and annealing temperature. Cation distribution associated magnetic ordering and anisotropy variation with the increasing Zn2+ concentration explains the observed magnetic behavior in these nanoparticle samples. Keywords Cu-ferrite . Substitution . XRD . Raman spectroscopy . Cation distribution . Magnetization

1 Introduction Spinel ferrite nanoparticles have attracted attention in research for their use in different fields of science, technology, biomedical, and environmental applications due to their excellent physical, chemical, electrical, magnetic, and biocompatible properties [1–10]. Due to the reduced size in nanoscale, they show magnetic behavior different from their bulk counterpart [11–14]. Properties of these nanomaterials can be tailored by substitution of diamagnetic or paramagnetic cations and their distribution in the spinel structure, grain sizes and their distribution, and surface morphology.

* Subasa C. Sahoo [email protected] 1

Department of Physics, Central University of Kerala, Tejaswini Hills, P.O. Periya, Kasaragod, Kerala 671320, India

2

Department of Physics, Amity School of Applied Sciences, Amity University, Mumbai-Pune Expressway, Bhatan, P.O. Somathne, Panvel, Mumbai, Maharashtra 410206, India

Magnetic properties of Cu-ferrite (CuFe2O4) have attracted much interest due to its different magnetic behavior in two different phases. It crystallizes either in tetragonal or in cubic phase. It has inverse spinel structure with 16 Fe3+ ions equally distributed among tetrahedr