Synthesis and Assembly of Monodisperse High-Coercivity Silica-Capped FePt Nanomagnets of Tunable Size, Composition, and Thermal Stability from Microemulsions


  • The authors gratefully acknowledge funding from NSF through DMR 0519081, NY state through the Focus Center, an Alexander von Humboldt Fellowship, a Honda Initiation Grant, and Prof. Bergmann Award from the US-Israel Binational Science Foundation. Supporting Information is available online from Wiley InterScience or from the author.


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A microemulsion approach to obtain high-coercivity (850 mT) FePt nanomagnets capped with a nanoscopic silica shell is reported (see figure). This versatile method allows the easy tuning of particle size and composition. The silica shell inhibits agglomeration and preserves the chemical stability of the particles up to 650 °C, and facilitates surface functionalization and particle assembly. These attributes are attractive for harnessing the nanomagnets for realizing novel devices and composites.