Structural and Magnetic Properties of Co‒Mn Codoped ZnO Nanoparticles Obtained by Microwave Solvothermal Synthesis

• Main Authors: Jacek Wojnarowicz, Myroslava Omelchenko, Jacek Szczytko, Tadeusz Chudoba, Stanisław Gierlotka, Andrzej Majhofer, Andrzej Twardowski, Witold Lojkowski
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Crystals
• Subjects: zinc oxide; nanoparticles; codoping; cobalt (II) ions; manganese (II) ions; microwave solvothermal synthesis; structural properties; magnetic properties; dilute magnetic semiconductors
• Online Access: https://www.mdpi.com/2073-4352/8/11/410

Zinc oxide nanoparticles codoped with Co²⁺ and Mn²⁺ ions (Zn_{(1−x−y)}Mn_xCo_yO NPs) were obtained for the first time by microwave solvothermal synthesis. The nominal content of Co²⁺ and Mn²⁺ in Zn_{(1−x−y)}Mn_xCo_yO NPs was x = y = 0, 1, 5, 10 and 15 mol % (the amount of both ions was equal). The precursors were obtained by dissolving zinc acetate dihydrate, manganese (II) acetate tetrahydrate and cobalt (II) acetate tetrahydrate in ethylene glycol. The morphology, phase purity, lattice parameters, dopants content, skeleton density, specific surface area, average particle size, average crystallite size, crystallite size distribution and magnetic properties of NPs were determined. The real content of dopants was up to 25.0% for Mn²⁺ and 80.5% for Co²⁺ of the nominal content. The colour of the samples changed from white to dark olive green in line with the increasing doping level. Uniform spherical NPs with wurtzite structure were obtained. The average size of NPs decreased from 29 nm to 21 nm in line with the increase in the dopant content. Brillouin type paramagnetism and an antiferromagnetic interaction between the magnetic ions was found for all samples, except for that with 15 mol % doping level, where a small ferromagnetic contribution was found. A review of the preparation methods of Co²⁺ and Mn²⁺ codoped ZnO is presented.