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Title: Effect of Sb substitution on crystal structure, texture and hard magnetic properties of melt-spun MnBi alloys

Abstract

Melt-spun Mn 50Bi 50-xSb x alloys with x ≤ 5 were prepared at different solidification rates and characterized both in the as-spun state and after annealing. In the as-spun alloys, the Sb substitution leads to the formation of a metastable phase, similar to the binary "quenched high-temperature phase" but without the superstructure of the latter and exhibiting a different – increasing – temperature dependence of coercivity. The new nanocrystalline metastable phase is not only itself characterized by a high room-temperature coercivity (in excess of 20 kOe), but upon annealing it transforms into a high-coercivity (up to 13.5 kOe) "low-temperature" α phase. However, the advantage of obtaining a high coercivity without the otherwise required milling made possible by the Sb substitution is undermined by the absence of a local crystallographic texture in the melt-spun alloys. The best combination of the isotropic hard magnetic properties realized for the Mn 55Bi 43.5Sb 1.5 composition is a remanence of 35.5 emu/g and a coercivity of 8.1 kOe. The annealed Sb-free Mn 50Bi 50 alloys did possess a local crystallographic alignment and, for high solidification rates, a moderate coercivity up to 5.6 kOe; however, they had an inadequate "rectangularity" in the demagnetization curve. The orthorhombicmore » compound known as MnBi 0.9Sb 0.1 and described earlier as antiferromagnetic was obtained in the annealed ribbons with x ≈ 5. The compound was found to order ferromagnetically between 200 K and ≈250 K and to exhibit a significant coercivity, 14.3 kOe at 50 K. Here, it is suggested that the MnBi 0.9Sb 0.1 may actually be a Sb-stabilized "new phase" observed earlier as metastable in the Bi–MnBi eutectic alloys.« less

Authors:
 [1];  [1];  [2]
  1. Univ. of Delaware, Newark, DE (United States)
  2. Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Univ. of Delaware, Newark, DE (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1504700
Grant/Contract Number:  
EE0007794
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Alloys and Compounds
Additional Journal Information:
Journal Volume: 792; Journal ID: ISSN 0925-8388
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; intermetallics; permanent magnets; nanostructured materials; rapid solidification; crystal structure; magnetization

Citation Formats

Gabay, Alexander, Hadjipanayis, George, and Cui, Jun. Effect of Sb substitution on crystal structure, texture and hard magnetic properties of melt-spun MnBi alloys. United States: N. p., 2019. Web. doi:10.1016/j.jallcom.2019.03.407.
Gabay, Alexander, Hadjipanayis, George, & Cui, Jun. Effect of Sb substitution on crystal structure, texture and hard magnetic properties of melt-spun MnBi alloys. United States. doi:10.1016/j.jallcom.2019.03.407.
Gabay, Alexander, Hadjipanayis, George, and Cui, Jun. Wed . "Effect of Sb substitution on crystal structure, texture and hard magnetic properties of melt-spun MnBi alloys". United States. doi:10.1016/j.jallcom.2019.03.407.
@article{osti_1504700,
title = {Effect of Sb substitution on crystal structure, texture and hard magnetic properties of melt-spun MnBi alloys},
author = {Gabay, Alexander and Hadjipanayis, George and Cui, Jun},
abstractNote = {Melt-spun Mn50Bi50-xSbx alloys with x ≤ 5 were prepared at different solidification rates and characterized both in the as-spun state and after annealing. In the as-spun alloys, the Sb substitution leads to the formation of a metastable phase, similar to the binary "quenched high-temperature phase" but without the superstructure of the latter and exhibiting a different – increasing – temperature dependence of coercivity. The new nanocrystalline metastable phase is not only itself characterized by a high room-temperature coercivity (in excess of 20 kOe), but upon annealing it transforms into a high-coercivity (up to 13.5 kOe) "low-temperature" α phase. However, the advantage of obtaining a high coercivity without the otherwise required milling made possible by the Sb substitution is undermined by the absence of a local crystallographic texture in the melt-spun alloys. The best combination of the isotropic hard magnetic properties realized for the Mn55Bi43.5Sb1.5 composition is a remanence of 35.5 emu/g and a coercivity of 8.1 kOe. The annealed Sb-free Mn50Bi50 alloys did possess a local crystallographic alignment and, for high solidification rates, a moderate coercivity up to 5.6 kOe; however, they had an inadequate "rectangularity" in the demagnetization curve. The orthorhombic compound known as MnBi0.9Sb0.1 and described earlier as antiferromagnetic was obtained in the annealed ribbons with x ≈ 5. The compound was found to order ferromagnetically between 200 K and ≈250 K and to exhibit a significant coercivity, 14.3 kOe at 50 K. Here, it is suggested that the MnBi0.9Sb0.1 may actually be a Sb-stabilized "new phase" observed earlier as metastable in the Bi–MnBi eutectic alloys.},
doi = {10.1016/j.jallcom.2019.03.407},
journal = {Journal of Alloys and Compounds},
number = ,
volume = 792,
place = {United States},
year = {2019},
month = {4}
}

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This content will become publicly available on April 3, 2020
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