Synthesis, Structural and Magnetic Characterization of Ni-Doped ZnO Diluted Magnetic Semiconductor

摘要

In the present work, Zn_1?xNi_xO (x = 0.02, 0.04, 0.06 and 0.08) nanoparticles have been synthesized using sol-gel auto-combustion method. The structural and magnetic properties of the Ni-doped ZnO samples annealed at 800^oC were characterized by Thermogravimetry/Differential thermal analysis (TG/DTA), X-ray diffractometer (XRD), Scanning electron microscope (SEM), FTIR spectrophotometer, Vibrating sample magnetometer (VSM) and Electron paramagnetic resonance (EPR) spectroscopy. Thermal analysis of as–prepared Zn_0.98Ni_0.02O sample shows that the synthesis process undergoes two stage weight losses before yielding Zn_0.98Ni_0.02O nanoparticles. Structural analysis using XRD reveals the formation of hexagonal wurtzite structure. SEM micrographs of Zn_0.98Ni_0.02O show the presence of spherical nanoparticles and the formation of well defined pores in the sample. FTIR study confirms the formation of ZnO with the stretching vibrational mode around 525 cm^-1. VSM measurement of sample (Zn_0.96Ni_0.04O) shows the hysteresis loop at room temperature confirms the ferromagnetic property of the sample. EPR spectra of the nickel doped ZnO samples suggest that the exchange interaction between Ni²⁺ ions results in the ferromagnetic nature of the samples.