真空熱処理によるFeナノ粒子基バルクの作製と軟磁気特性の発現

概要

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The magnetic properties of Fe nanoparticle-based bulk material, which was fabricated with a through post-annealing process under vacuum conditions, were investigated to develop a new Fe-based soft magnetic material. Fe nanoparticles (NPs) retained uniform-size and narrow-size distributions at a post annealing temperature (Ta) of 473K. Their assembly was self organized, which is referred to as nano size periodicity. Soft magnetic properties were obtained at 1.7±0.2 Oe of coercivity at room temperature, and 179 emu/gnet of saturation magnetization was obtained at 5K by using Ta=473 K . Above Ta= 573 K, saturation magnetization decreased and coercivity was increased. High temperature post-annealing above 523 K caused NP growth and the transformation α-Fe to Fe3C, which originated from carbon impurities in the surfactant. Thus, the low-temperature post-annealing process plays an important role in achieving high performance soft magnetic properties using Fe NP-based bulk material by desorbing of surfactants without the formation of iron carbide.