Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Structural, magnetic and electrical properties along with antifungal activity & adsorption ability of cobalt doped manganese ferrite nanoparticles synthesized using combustion route Anuja B. Naik, Pranav P. Naik ∗ , Snehal S. Hasolkar, Diksha Naik H. P. S. M.‘s Ganpat Parsekar College of Education, Harmal, Pernem, Goa, 403524, India ARTICLE INFO Keywords: Ferrite nanoparticles Combustion method Particle size Antifungal activity Adsorption ABSTRACT Ultrafne powders of Cobalt doped manganese ferrite with elemental composition Mn 1-x Co x Fe 2 O 4 (x = 0.2, 0.4, 0.6, 0.8) were synthesized using combustion method. The formation of the pure cubic spinel phase of ferrite structure was confrmed using X-ray difraction and Fourier transform infrared spectroscopy. Structural para- meters such as lattice constant, X-ray density, mass density, porosity, and cell volume were seen to be greatly infuenced by cobalt doping. The surface morphology of the nanocrystalline samples was studied using a scanning electron microscope. The particle size distribution was determined using a Transmission electron microscope and nanograins of the samples were found to have dimensions in the range 15 nm–30 nm. It also showed its dependence on the extent of cobalt inclusion. Variation of magnetization and magnetic moment as a function of magnetic feld and temperature was investigated using a vibrating sample magnetometer (VSM). The parameters such as saturation magnetization ‘M S ’ and inversion temperature T I were seen to depend upon Co +2 concentration. The variation dielectric constant ‘Ԑ’ as a function of frequency was studied. Antifungal activity of these ferrite nanoparticles against Rhizopus fungi was also investigated at room temperature. The antifungal activity was seen to increase with increasing Co +2 content in the manganese ferrite structure and hence cobalt doped manganese ferrites are proposed as a candidate material for industries manufacturing antifungal products. The adsorption studies were also investigated using Methylene dye as the adsorbate. 1. Introduction The investigation on utility magnetic ferrite nanomaterials in the antimicrobial and anti-fungal application is gaining much attention, as several compositions of ferrite materials show superior activity toward microbes and fungus [1]. Ferrites are semiconductors belonging to the ferrimagnetic class of magnetic materials with general formula AB 2 O 4 , where A is a divalent transition metal ion such as Cr +2 , Mn +2 , Fe +2 , Co +2 , Ni +2 , Cu +2 or Zn +2 occupying the tetrahedral site and B is a trivalent transition metal ion (generally Fe +3 ) occupying the octahedral site. Ferrites are known to have a cubic spinal structure comprising of 16 tetrahedral sites and 32 octahedral sites. The structural, magnetic and electrical properties of these materials are closely governed by the cations occupying these tetrahedral and the octahedral sites [2–8]. Generally, 8 out of 16 tetrahedral sites and 16 out of 32 octahedral sites are occupied by the divalent and trivalent metal ions. In addition to unique properties such as high resistivity, high saturation magnetiza- tion, low hysteresis loss, these materials possess antifungal and antimicrobial properties which are being explored by researchers all over the globe. Ferrites are used in applications such as magnetic in- gredients in microelectronics, manufacturing magnetic liquids, in- ductors, humidity sensors, magnetic resonance imaging, microwave refection, hyperthermia, and targeted drug-delivery processes. They also fnd their applications in catalysts, converters, high-density data- storage materials, and antenna bodies [8–13]. MnFe 2 O 4 is a well-known member of this spinal ferrite family with fne structural, magnetic and electrical properties. The characteristic properties of manganese ferrites can be improved by incorporating magnetic divalent metal ion such as Co +2 in its chemical structure. The inclusion of cobalt ions to manganese ferrite improves the coercive properties of the material due to enhancement in magneto-crystalline anisotropy. This enhancement in magnetocrystalline anisotropy results from the spin coupling of the cobalt and iron ions [14]. Cobalt doped ferrite is also known to possess excellent properties such as increased drug solubility, stability and reduced side efects that attract biomedical applications [15,16] Researchers are trying to https://doi.org/10.1016/j.ceramint.2020.05.177 Received 11 April 2020; Received in revised form 9 May 2020; Accepted 18 May 2020 ∗ Corresponding author. E-mail addresses: anu26naik@gmail.com (A.B. Naik), drppn1987@gmail.com (P.P. Naik). Ceramics International xxx (xxxx) xxx–xxx 0272-8842/ © 2020 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Please cite this article as: Anuja B. Naik, et al., Ceramics International, https://doi.org/10.1016/j.ceramint.2020.05.177