2005/04/30 by Shinpei Yamamoto, Yasumasa Morimoto, Teruo Ono +1 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Characterization and Applications of Magnetic Nanoparticles #Chemical engineering #Coalescence (physics) #Coating #Coercivity #Condensed matter physics #Dispersity #Hysteresis #Magnet #Magnetic Properties and Synthesis of Ferrites #Magnetic field #Magnetic hysteresis #Magnetic properties of thin films #Magnetism #Magnetization #Materials science #Nanocrystal #Nanotechnology #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/1.1995959
14 pages, 5 figures
arxiv created 2005/04/30 · openalex publication_date 2005/07/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report synthesis of monodisperse L10-FePt nanocrystals that are not only superior in magnetism but also easy to handle through being dispersible in solvents. Thanks to a thick SiO2 coating, the thermal treatment needed to form the L10 structure can be done even at 900°C without inducing coalescence and coarsening. The protecting shell was thereafter removed in a specific way that enabled us to recover the L10-FePt nanocrystals in a water dispersion. The SiO2-coated nanocrystals show a high coercivity of 18.5kOe at room temperature in spite of their core size of only 6.5nm in diameter, and the hysteresis loop of the water-dispersed nanocrystals, which were frozen under an external field, was almost rectangular indicating that their magnetic and structural orientation could be attained.