Rapid synthesis and room temperature ferromagnetism of Ni doped ZnO DMS nanoflakes

NixZn1-xO (x=0.0, 0.05, 0.1, and 0.2) nanoflakes were successfully synthesized by microwave-assisted combustion method. The structural and morphological characterizations of the as synthesized samples were done by using XRD and SEM. Optical and magnetic properties of NixZn1-xO samples were analyzed by a UV-vis spectrophotometer and VSM magnetometer. XRD patterns indicate the hexagonal wurtzite structure of all samples without any impurity phases. SEM micrographs indicated that all samples have grains mainly in the form of nanoflakes. From UV-vis spectra of the samples, it is observed that pure ZnO sample has an energy band gap of 3.13 eV and it is decreased by Ni doping. Magnetic property investigations have revealed that all samples have room-temperature ferromagnetic properties. The saturation magnetizations of the samples were increased by Ni doping. The difference between temperature dependent magnetization curves (the difference between field cooled-FC and zero field cooled-FC magnetization curves) also indicated the ferromagnetic behaviors of the samples at all measuring temperatures with a Curie temperature above the room temperature. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.