Hard magnetic property enhancement of Co7Hf-based ribbons by boron doping

H. W. Chang; M. C. Liao; C. W. Shih; W. C. Chang; C. C. Yang; C. H. Hsiao; H. Ouyang

doi:10.1063/1.4901737

Hard magnetic property enhancement of Co₇Hf-based ribbons by boron doping

H. W. Chang, M. C. Liao, C. W. Shih, W. C. Chang, C. C. Yang, C. H. Hsiao, H. Ouyang

Department of Physics

Research output: Contribution to journal › Article › peer-review

21 Scopus citations

Abstract

Hard magnetic property enhancement of melt spun Co₈₈Hf₁₂ ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH)_max) of 2.6 MGOe and intrinsic coercivity (_iH_c) of 1.5 kOe for B-free Co₈₈Hf₁₂ ribbons to (BH)_max = 7.7 MGOe and _iH_c = 3.1 kOe for Co₈₅Hf₁₂B₃ ribbons but also improve the Curie temperature (T_C) of 7:1 phase. The (BH)_max value achieved in Co₈₅Hf₁₂B₃ ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co₁₁Hf₂B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co₇Hf (7:1) crystal structure as interstitial atoms, forming Co₇HfB_x, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (B_r) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co₇HfB_x phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co₇Hf-based ribbons.

Original language	English
Article number	192404
Journal	Applied Physics Letters
Volume	105
Issue number	19
DOIs	https://doi.org/10.1063/1.4901737
State	Published - 10 Nov 2014

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title = "Hard magnetic property enhancement of Co7Hf-based ribbons by boron doping",

abstract = "Hard magnetic property enhancement of melt spun Co88Hf12 ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH)max) of 2.6 MGOe and intrinsic coercivity (iHc) of 1.5 kOe for B-free Co88Hf12 ribbons to (BH)max = 7.7 MGOe and iHc = 3.1 kOe for Co85Hf12B3 ribbons but also improve the Curie temperature (TC) of 7:1 phase. The (BH)max value achieved in Co85Hf12B3 ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co11Hf2B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co7Hf (7:1) crystal structure as interstitial atoms, forming Co7HfBx, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (Br) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co7HfBx phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co7Hf-based ribbons.",

author = "Chang, {H. W.} and Liao, {M. C.} and Shih, {C. W.} and Chang, {W. C.} and Yang, {C. C.} and Hsiao, {C. H.} and H. Ouyang",

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T1 - Hard magnetic property enhancement of Co7Hf-based ribbons by boron doping

AU - Chang, H. W.

AU - Liao, M. C.

AU - Shih, C. W.

AU - Chang, W. C.

AU - Yang, C. C.

AU - Hsiao, C. H.

AU - Ouyang, H.

PY - 2014/11/10

Y1 - 2014/11/10

N2 - Hard magnetic property enhancement of melt spun Co88Hf12 ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH)max) of 2.6 MGOe and intrinsic coercivity (iHc) of 1.5 kOe for B-free Co88Hf12 ribbons to (BH)max = 7.7 MGOe and iHc = 3.1 kOe for Co85Hf12B3 ribbons but also improve the Curie temperature (TC) of 7:1 phase. The (BH)max value achieved in Co85Hf12B3 ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co11Hf2B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co7Hf (7:1) crystal structure as interstitial atoms, forming Co7HfBx, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (Br) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co7HfBx phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co7Hf-based ribbons.

AB - Hard magnetic property enhancement of melt spun Co88Hf12 ribbons by boron doping is demonstrated. B-doping could not only remarkably enhance the magnetic properties from energy product ((BH)max) of 2.6 MGOe and intrinsic coercivity (iHc) of 1.5 kOe for B-free Co88Hf12 ribbons to (BH)max = 7.7 MGOe and iHc = 3.1 kOe for Co85Hf12B3 ribbons but also improve the Curie temperature (TC) of 7:1 phase. The (BH)max value achieved in Co85Hf12B3 ribbons is the highest in Co-Hf alloy ribbons ever reported, which is about 15% higher than that of Co11Hf2B ribbons spun at 16 m/s [M. A. McGuire, O. Rios, N. J. Ghimire, and M. Koehler, Appl. Phys. Lett. 101, 202401 (2012)]. The structural analysis confirms that B enters the orthorhombic Co7Hf (7:1) crystal structure as interstitial atoms, forming Co7HfBx, in the as-spun state. Yet B may diffuse out from the 7:1 phase after post-annealing, leading to the reduction of Curie temperature and the magnetic properties. The uniformly refined microstructure with B-doping results in high remanence (Br) and improves the squareness of demagnetization curve. The formation of interstitial-atom-modified Co7HfBx phase and the microstructure refinement are the main reasons to give rise to the enhancement of hard magnetic properties in the B-containing Co7Hf-based ribbons.

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DO - 10.1063/1.4901737

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SN - 0003-6951

VL - 105

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 19

M1 - 192404

ER -

Hard magnetic property enhancement of Co7Hf-based ribbons by boron doping

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Hard magnetic property enhancement of Co₇Hf-based ribbons by boron doping