Synthesis and characterisation of iron platinum nanoparticles

Abstract

This thesis investigates the synthesis and characterization of FePt nanoparticles, a material which is a promising candidate for use as an ultra-high density magnetic storage medium; relevant literature is reviewed in chapter one. Chapter two gives full details of the characterisation techniques and physical property measurements employed throughout the work described in the following chapters. This includes powder X-ray diffraction, SQUID magnetometry, transmission electron microscopy, extended X- ray fluorescence spectroscopy and Rutherford backscattering. Chapter three describes the synthesis and characterisation of FePt nanoparticles prepared by a route presented in the literature as well as one developed during this study. Chapter four describes a systematic investigation into the Rietveld refinement of powder X-ray diffraction data of iron platinum nanoparticles. From the study it is concluded which of the methodologies presented is most suitable for use in further work on iron platinum nanoparticle studies. Chapter five describes a number of in-situ variable temperature X-ray diffraction studies designed to investigate the order-disorder transition in FePt nanoparticles. A comparison between this transition in samples made via both synthetic routes discussed in chapter three is made before analysing in-depth data in order to provide information about the phase transition and its relationship with precise synthetic conditions. Chapter six describes work done on FePt nanoparticles to determine if EXAFS measurements can be obtained and modelled such that conclusions can be drawn as to the degree of order of samples prepared via different methods. Chapter seven describes a variety of magnetic studies designed to investigate the structure and properties of FePt nanoparticles. The first part of the chapter focuses on typical experiments and what use they are whilst the second part discusses the methodology and equipment required to study the phase transition of iron platinum nanoparticles, i.e. variable temperature magnetic studies.