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Structural and Magnetic model of self-assembled FePt nanoparticle arrays

Technical Report ·
DOI:https://doi.org/10.2172/826934· OSTI ID:826934
Chemically ordered, self-assembled FePt nanoparticle arrays with high magnetic anisotropy are considered a candidate medium for data storage beyond 1 Tbit/in{sup 2}. We report comprehensive structural and magnetic studies on thin (3 layer) assemblies of polyethylenimine (PEI) and 4 nm Fe{sub 58}Pt{sub 42} nanoparticles using X-ray diffraction, small angle neutron scattering and magnetometry. We show that prior to annealing FePt nanoparticles in the PEI-FePt assembly consist of a metallic, magnetic core surrounded by a weakly magnetic or non-magnetic shell. High temperature annealing creates the desired L1{sub 0} chemical ordering and results in high coercivity FePt nanoparticles. However, we find that the high temperatures necessary to establish full chemical ordering leads to particle sintering and agglomeration. Understanding the magnetic and physical properties of these assemblies allows future research directions to be clarified for nanoparticle arrays as data storage media.
Research Organization:
Stanford Linear Accelerator Center, Menlo Park, CA (US)
Sponsoring Organization:
USDOE Office of Science (US)
DOE Contract Number:
AC03-76SF00515
OSTI ID:
826934
Report Number(s):
SLAC-PUB-10450
Country of Publication:
United States
Language:
English