Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Microstructure and magnetic behavior of (Mg/Ni) co-doped ZnO nanoparticles C. Boyraz a , N. Dogan b , L. Arda c, ⁎ a Marmara University, Faculty of Technology, Department of Mechanical Engineering, Goztepe, 34722 Istanbul, Turkey b Gebze Technical University, Faculty of Science, Department of Physics, 41400 Gebze, Kocaeli, Turkey c Bahcesehir University, Faculty of Engineering and Naturel Sciences, Department of Mechatronic Engineering, Ciragan Cad. Osmanpasa Mektebi Sok., Besiktas, 34349 Istanbul, Turkey ARTICLE INFO Keywords: Zn 0.95-x Mg x Ni 0.05 O Magnetic properties Sol-gel Nanostructures ABSTRACT Zn 0.95-x Mg x Ni 0.05 O nanoparticles were synthesized using sol-gel technique by varying x values from 0.01 to 0.05 in step of 0.01. The annealing temperature was optimized and 4% Ar-H 2 gas was used for the annealing process to obtain single phase Zn 0.95-x Mg x Ni 0.05 O samples. The possible lost weights of samples in a wide temperature range for Zn 0.95-x Mg x Ni 0.05 O samples were investigated by differential thermal analysis and thermo gravimetric analysis. X-ray diffraction of Zn 0.95-x Mg x Ni 0.05 O samples exhibited single phase with an- nealing process under 4% Ar-H 2 gas at 450 °C. A structural distortion was revealed by replacing Zn 2+ by Mg 2+ and Ni 2+ due to the ionic radius difference which gave rise to a decrease in the crystallite size. The SEM images showed cluster shape distribution in quasi-spherical particles and were almost observed in all frames with ag- glomeration. Magnetization measurements were conducted at room temperature for all samples under the DC magnetic field for magnetization curves (M vs. H). The magnetization curves of Mg and Ni -doped ZnO systems exhibited a ferromagnetic behavior at room temperature. 1. Introduction Zinc oxide (ZnO) and ZnO–based semiconductors are promising candidates with many commercial and technological applications such as optoelectronics, cosmetics, surface acoustic wave devices, spin- tronics, varistors, and biomaterials [1–6]. Doped ZnO with varying elements exhibit exciting physical properties and bring new perspec- tives to researchers for developing new technologies. Doped ZnO also presents different physical behaviors depended on synthesizing condi- tions [7]. Potential dilute magnetic semiconductor (DMSs) material ZnO has a large binding energy (60 eV) and wide band gap energy (3.3 eV) [8]. The band gaps and other physical properties can be con- trolled by doping different dopant elements such as Fe, Co, Ni, Cr, V, and Mg [5–12]. ZnO doped magnesium oxide (MgO), (Zn1-xMgxO, (ZMO)) compound is a promising candidate for band gap engineering with several deposition methods such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), metal-organic chemical vapour de- position (MOCVD) and sol-gel method [12–15]. ZnO brings an alter- native with its advantage of higher exciton binding energy compared to the existing technology AlInGaN for UV light emitters. Therefore, Ag, N, Co, Ru, S, Pt, C, Au, and ZnO combinations are used as a converter from UV sensitive material to a visible-light irradiated material [16–19]. Currently, interests in developing DMS nanoparticles and thin films enable the link between the advanced semiconductor technologies and magnetic properties [20]. Dilute magnetic semiconductor (DMSs) doped with varying transition metal (TM) presents varying magnetic properties and the origin of certain properties in magnetic behaviors still need to be clarified [21,22]. Therefore, many researchers have pointed out ZnO semiconductors with varying dopant ratios and ele- ments using magnetic-chemical properties at room temperature to im- prove device technologies such as magnetic memories (MRAM), spin- LED, logic devices [23–25]. Peculiar magneto resistance behaviors correlated with d shell electron interaction of the TM-doped ZnO are still a matter of discussion. In the literature, Ni or Mg-doped ZnO nanoparticles have been widely studied. In this paper, for the first time, the structural, mor- phological, and magnetic characteristics of Zn 0.95-x Mg x Ni 0.05 O (x = 0.01 to 0.05) nanoparticles have been synthesized by the sol-gel method providing the advantages such as better homogeneity, low cost, simplicity, and continuous processing at room temperature. http://dx.doi.org/10.1016/j.ceramint.2017.08.184 Received 9 August 2017; Received in revised form 25 August 2017; Accepted 28 August 2017 ⁎ Corresponding author. E-mail address: lutfi.arda@eng.bau.edu.tr (L. Arda). Ceramics International xxx (xxxx) xxx–xxx 0272-8842/ © 2017 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Please cite this article as: Boyraz, C., Ceramics International (2017), http://dx.doi.org/10.1016/j.ceramint.2017.08.184