X-ray Absorption and Diffraction Studies of Thin Polymer/FePt Nanoparticle Assemblies
We have produced assemblies of FePt nanoparticles using high temperature solution phase synthesis and polymer-mediated layer-by-layer deposition allowing precise control of the particle self-assembly. The as-deposited particles have a narrow size distribution offering the potential for use as ultra-high density magnetic storage media and ultimately storage of one bit per individual nanoparticle. Vibrating sample magnetometry was applied to measure the magnetic properties of the particle assemblies as a function of anneal condition while Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy and x-ray diffraction (XRD) were used to investigate the chemical nature and structural properties. It was found that the coercivity can be as high as 22.7 kOe for samples annealed at 800 C, the moment density (normalized to the particle volume) has a maximum of 1140 emu/cm{sup 3} for annealing at 650 C equal to the value for bulk FePt. NEXAFS spectroscopy shows that the Fe in the as-deposited assemblies is partly oxidized, and the oxidation is greatly reduced by annealing. XRD indicates an increased formation of the chemically ordered, high anisotropy L1{sub 0} phase and the onset of nanoparticle agglomeration for annealing at higher temperatures.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 813354
- Report Number(s):
- SLAC-PUB-9989; TRN: US0303874
- Resource Relation:
- Other Information: PBD: 20 Jun 2003
- Country of Publication:
- United States
- Language:
- English
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