Structural and magnetic model of self-assembled FePt nanoparticle arrays

T Thomson, MF Toney, S Raoux, Stephen Leslie Lee, S Sun, CB Murray, BD Terris

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


Chemically ordered, self-assembled FePt nanoparticle arrays with high magnetic anisotropy are considered as a candidate medium for data storage beyond 1 Tbit/in2. We report comprehensive structural and magnetic studies on thin (three-layer) assemblies of polyethylenimine (PEI) and 4 nm Fe58Pt42 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 nonmagnetic shell. High temperature annealing creates the desired L1(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. (C) 2004 American Institute of Physics.

Original languageEnglish
Pages (from-to)1197
Number of pages1197
JournalJournal of Applied Physics
Issue number2
Publication statusPublished - 15 Jul 2004




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