Effects of doping ferromagnetic transition elements into (PT-AU) nanoparticles on structural and magnetic properties

This thesis study aims to investigate the structural and magnetic properties of Pt-Au based nanoparticles (NPs) doped with equal ratios of ferromagnetic transition elements Fe, Co, and Ni, and produced using a modified poliol method. The focus is on the effects of ternary metallic alloy NPs on structural morphologies and magnetic behaviors, and their compatibility with each other. X-ray diffraction (XRD) and Rietveld refinement analysis were applied to determine the crystal structures of binary and ternary atomic NPs, and it was determined that all NPs have a face-centered cubic crystal structure belonging to the fm-3m space group. In addition to determining the surface morphologies and size distributions of the NPs through scanning electron microscope (SEM) images, the elemental stoichiometric calculations of the NPs were performed using X-ray spectrometer (EDS). For the magnetic results of the NPs, magnetization measurements were carried out using a physical property measurement system (PPMS), depending on the magnetic field and temperature. As a result of measurements carried out at 5-350 K with zero-field cooling and 250 Oe constant external field cooling, the magnetic behavior and blocking temperatures of the materials were determined as 198 K for Pt-Au, and 14 K and 55 K for Fe and Co atom doping, respectively. Additionally, by examining the hysteresis curves of the material against ±3 T magnetic field at different temperatures, the highest Hc value was observed in PtAuCo NPs at 5 K, while Ms was calculated as 17.8 emu/g for PtAuFe at 5 K. As a result, magnetically recyclable materials at room temperature were produced by imparting magnetic properties to Pt-Au NPs, which are valuable noble metals. Thus, it is hoped that these ternary metallic NPs will offer a new perspective to the literature and technology. Keywords: Pt-Au based trimetallic NPs, structural and magnetic properties, modified poliol synthesis method.