Fabrication and Magnetic Properties of Nano-particles by Ion Beam Induced Chemical Vapor Deposition (IBICVD)

本研究旨在开发一种利用离子束诱导化学气相沉积(IBICVD)技术制备纳米粒子的技术，并结合制备条件和结构对其磁性能进行表征，努力建立双束沉积方法的制备条件，以重复性地制备具有高磁各向异性的不同合金成分的FePT和CoPt亚微米粒子。结果表明：1.首次成功制备了Fe-铂和Co-铂二元合金的亚微米级颗粒。结果表明，所制得的FePT颗粒具有10^6erg/cc量级的高磁各向异性。然而，这个值仍然低于FePT的有序L10相的值。这种较低的磁各向异性的原因被发现是由于存在fcc和fct两个相。发现亚微米级的CoPt颗粒具有很高的磁各向异性，尽管它们是非晶态结构。高温退火后形成面心立方和面心立方两相，但没有得到磁各向异性的增强。这些工作在INTERMAG和MMM等主要国际会议上发表过，也发表在主要科学期刊上。

The present research aims to develop a technique to fabricate nano-particles by Ion Beam Induced Chemical Vapor Deposition (IBICVD) technique, and characterize magnetic properties in conjunction with fabrication condition and in turn structure.Many efforts were taken for establishing fabrication condition of Dual Beam deposition methods so as to reproducibly fabricate submicron particles of various alloy compositions of FePt and CoPt with high magnetic anisotropy. As a result,1. Particles of submicron size for Fe-Pt and Co-Pt binary alloys were for the first time successfully fabricated.2. The particles of FePt thus obtained are found to exhibit high magnetic anisotropy of the order of 10^6erg/cc. However, this value is still lower than that for the ordered L1o phase of FePt. The reason or this lower magnetic anisotropy is found to be due the presence of two phases of fcc and fct.3. The particles of CoPt in submicron size are found to possess high magnetic anisotropy even though they are of amorphous structure.4. After annealed at high temperatures, they become of two phases of fcc and fct, but no enhancement of magnetic anisotropy is obtained.These works were presented at major international conferences including Intermag and MMM, and also were published in major scientific journals.