Date of this Version
JOURNAL OF APPLIED PHYSICS 115 (2014)
Nanocrystalline Ti0.75Zr0.25Fe2+x (x=0-0.4) and Ti0.75-yByZr0.25Fe2.4 (y=0-0.35) with high saturation magnetization have been fabricated by the melt-spinning technique. Nanocrystalline Ti0.75Zr0.25Fe2+x consists of the hexagonal C14 Laves phase (Ti,Zr)Fe2. Fe addition decreases the lattice parameter a and shrinks the cell volume. The antiferromagnetic Fe-Fe interactions may decrease with the increase of x, leading to a significant enhancement of saturation polarization (Js) and Curie temperature (Tc). The magnetocrystalline anisotropy constant K also increases with increasing x. Excessive Fe addition (x>0.25) may induce structural disorder which lowers the Js and Tc. Nanocrystalline Ti0.75-yByZr0.25Fe2.4 is composed of hexagonal (Ti,Zr)Fe2 and Fe-rich amorphous phases with relatively high Js. The lattice parameters a, c and cell volume V are almost unchanged with the increase of y for y≥0.16. Simultaneously, the Tc of (Ti,Zr)Fe2 remains unchanged, indicating that B does not enter this lattice but takes part in forming the amorphous phase, in good agreement with the X-ray diffraction results. The volume fraction of the amorphous phase increases with the increase of B content and results in a large enhancement of Js up to 10.8 kG. Further B addition (y>0.30) decreases Js, possibly due to the decrease of the Js of the amorphous phase.