FePt及FePtB奈米晶薄帶磁性、相變化與交換藕合效應之研究

• Main Authors: Cheng Wu Chang, 張正武
• Other Authors: W. C. Chang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/15723897269832385807

碩士 === 國立中正大學 === 物理系 === 92 === Magnetic properties, phase evolution, and exchange coupling effect of FePt and FePtB nanocomposite ribbons have been investigated in this thesis. The nanocomposites of FexPt100-x, (FeyPt1-y)82B18, and (Fe67.5Pt32.5)100-zBz alloy ribbons were prepared by melt-spinning method. With increasing Fe content, the sauturation magnetization increased, on the contrary, coercivity and the Curie temperature of ordered -FePt phase and disordered -FePt phase decreased in binary FexPt100-x (x = 50-70) alloy ribbons. For binary FexPt100-x series ribbons. The optimal magnetic properties of iHc = 2.1 kOe and r = 32.3 emu/g were achieved in the Fe50Pt50 ribbon. Addition of B in the (FeyPt1-y)82B18 (y = 0.5-0.7) series ribbons not only leads to the formation of some magnetically soft ferrous boride phases, but also effectively refines grain size. Accordingly, the magnetic properties and intergranular exchange coupling effect of ribbons were enhanced. The -FePt, -FePt, and Fe2B phase were present at y = 0.5, 0.6, and 0.65 ribbons, and Fe3B was appeared for y = 0.675 and 0.7. In this series ribbons, the optimal magnetic properties of Br = 8.9 kG, iHc = 8.2 kOe, (BH)max = 13.2 MGOe were achieved in the (Fe0.675Pt0.325)82B18 ribbon. Finally, in the (Fe67.5Pt32.5)100-zBz (y = 12-20) alloy ribbons system, the addition of sufficient boron not only promotes the  transformation but also leads to some soft phase, Fe2B and Fe3B. New record magnetic properties with Br of 9.4 kG, iHc of 7.5 kOe, and (BH)max of 14.0 MGOe have been obtained in (Fe0.675Pt0.325)84B16 alloy ribbons.