Direct formation of L1 0 FePt in as-cast FePt-based magnetic nanocomposite ribbons without post-synthesis annealing
2011; Institute of Physics; Volume: 44; Issue: 36 Linguagem: Inglês
10.1088/0022-3727/44/36/365002
ISSN1361-6463
Autores Tópico(s)Magnetic Properties and Applications
ResumoA novel nanocomposite FePt-based exchange-coupled magnet has been synthesized and structurally and magnetically characterized. We report for the first time the direct formation of the L 1 0 FePt phase without the need for post-synthesis annealing procedures in Fe-Pt-based melt-spun ribbons, obtained by a conventional melt spinning method. The structure and magnetic properties are investigated and the occurrence of the L 1 0 ordered phase in the as-cast state of Fe–Pt–Ag–B melt-spun ribbons is confirmed by XRD and magnetic measurements. A microstructure consisting of fine, uniformly dispersed, 22–24 nm FePt grains dispersed within a soft magnetic matrix is observed by scanning transmission electron microscopy imaging. Coercive fields as high as 727 kA m −1 , saturation magnetization of about 1.2 T and energy product around 87 kJ m −3 are determined from 270 K hysteresis loops of the as-cast ribbons, making one of the best FePt-based nanocomposite magnet ribbons even without further annealing treatments.
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