Magnetocrystalline anisotropy of partially ordered Fe-Pt nanoparticles directly synthesized with microwave-polyol method

• Published in: IEEE transactions on magnetics Vol. 41; no. 10; pp. 3880 - 3882
• Main Authors: Kitamoto, Y., Minami, R., Shibata, Y., Chikata, T., Kato, S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.10.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Chemical analysis; Coercive force; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Iron; Magnetic analysis; Magnetic anisotropy; Magnetism; Magnetization decay; magnetocrystalline anisotropy; Materials science; Microwave theory and techniques; MÖssbauer spectroscopy; nanoparticle; Nanoparticles; ordered alloy; Other topics in materials science; Perpendicular magnetic anisotropy; Physics; Saturation magnetization; Nanoparticles; Magnetization; Ordered alloy; Magnetic anisotropy; Mossbauer spectroscopy; Microwave irradiation; Moessbauer spectroscopy; nanoparticle; Magnetization decay; magnetocrystalline anisotropy; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2005.854953

We report direct synthesis of chemically ordered Fe-Pt nanoparticles using microwave irradiation during polyol reaction at 250/spl deg/C without any post-synthesis treatments. Mo/spl uml/ssbauer analysis exhibits the Fe-Pt nanoparticles having partially ordered L1/sub 0/ structure, and the fraction of Fe atoms in the chemically ordered L1/sub 0/ structure to the total amount of Fe atoms is 57%. Coercivity and saturation magnetization of the partially ordered Fe-Pt nanoparticles are 3.0 kOe and 57 emu/g at room temperature, respectively. An evaluation of the anisotropy-field distribution using Flanders-Shtrikman method reveals that the Fe-Pt sample includes nanoparticles with anisotropy fields much lower than the anisotropy field H/sub k//sup Wr/ of 85 kOe obtained by rotational hysteresis loss measurements.