Hf doping effect on hard magnetism of nanocrystalline Zr 18-xHfxCo82 ribbons

I. A. Al-Omari, W. Y. Zhang, Lanping Yue, R. Skomski, J. E. Shield, X. Z. Li, D. J. Sellmyer

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Abstract

The effects of substituting Zr by Hf on the structural and the magnetic properties of the nanocrystalline rapidly solidified Zr18-xHf xCo82 ribbons (x = 0, 2, 4, and 6) have been studied. X-ray diffraction and thermomagnetic measurement results indicated that upon rapid solidification processing four magnetic phases occur: rhombohedral Zr 2Co11, orthorhombic Zr2Co11, hcp Co, and cubic Zr6 Co23 phases. Microstructure analysis results showed the reduction in the percentage of the soft-magnetic phase (Co) compared to the hard-magnetic phase (Zr2Co11 (rhombohedral)) with the increase in the Hf concentration. All the samples under investigation have ferromagnetic nature, at 4.2 K and at room temperature. The coercive force (Hc) and the saturation magnetization (Ms) are found to linearly increases with x (x ≤ 2), then Hc slightly increases and Ms slightly decreases with increasing x. The maximum energy product (BH})max at room temperature is found to increases with increasing x reaching a maximum value for x = 4. The magnetocrystalline anisotropy parameter of these samples are calculated to be K = 1.1 MJ/m 3 and independent of Hf concentration. The above results indicate that the replacement of Zr by Hf improves the hard-magnetic properties of this class of rear-earth-free nanocrystalline permanent magnet materials.

Original languageEnglish
Article number6559021
Pages (from-to)3394-3397
Number of pages4
JournalIEEE Transactions on Magnetics
Volume49
Issue number7
DOIs
Publication statusPublished - 2013

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Keywords

  • Energy
  • magnetization
  • microstructure
  • nanomaterials
  • permanent magnets

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

Cite this

Al-Omari, I. A., Zhang, W. Y., Yue, L., Skomski, R., Shield, J. E., Li, X. Z., & Sellmyer, D. J. (2013). Hf doping effect on hard magnetism of nanocrystalline Zr 18-xHfxCo82 ribbons. IEEE Transactions on Magnetics, 49(7), 3394-3397. [6559021]. https://doi.org/10.1109/TMAG.2013.2245498