Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering

Yu Chun Chen; Giuliano Gregori; Bastian Rheingans; Wenting Huang; Helmut Kronmüller; Gisela Schütz; Eberhard Goering

doi:10.1016/j.jallcom.2020.154605

Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering

Yu Chun Chen, Giuliano Gregori, Bastian Rheingans, Wenting Huang, Helmut Kronmüller, Gisela Schütz, Eberhard Goering

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

12 Scopus citations

Abstract

In this study, we present that anisotropic MnBi bulk magnets can be obtained using spark-plasma-sintering technique (SPS). Grain misalignment was suppressed by either external field or addition of appropriate polymer binder. Various microstructures were effectively achieved during SPS processing, and lead to distinct magnetic performance. Microstructure analysis reveals that the coercive field of the SPS-compacted magnets declines strongly with increasing grain size. Bi-rich residue clearly plays a role in magnetic decoupling to enhance the coercive field, whereas the exchange coupling mediated by excess Mn reduces it dramatically. In addition, the amount and distribution of Mn and Bi residue has a profound influence on the thermal magnetic stability of sintered MnBi magnets. We suggest that fast consolidation methods like SPS technique enable to tailor the microstructure of bulk magnetic products to meet specific application requirements.

Original language	English
Article number	154605
Journal	Journal of Alloys and Compounds
Volume	830
DOIs	https://doi.org/10.1016/j.jallcom.2020.154605
State	Published - 25 Jul 2020
Externally published	Yes

Keywords

Microstructure
MnBi
SPS

Access to Document

10.1016/j.jallcom.2020.154605

Cite this

@article{48deb51c40f44ed499c4b4eb3793fda9,

title = "Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering",

abstract = "In this study, we present that anisotropic MnBi bulk magnets can be obtained using spark-plasma-sintering technique (SPS). Grain misalignment was suppressed by either external field or addition of appropriate polymer binder. Various microstructures were effectively achieved during SPS processing, and lead to distinct magnetic performance. Microstructure analysis reveals that the coercive field of the SPS-compacted magnets declines strongly with increasing grain size. Bi-rich residue clearly plays a role in magnetic decoupling to enhance the coercive field, whereas the exchange coupling mediated by excess Mn reduces it dramatically. In addition, the amount and distribution of Mn and Bi residue has a profound influence on the thermal magnetic stability of sintered MnBi magnets. We suggest that fast consolidation methods like SPS technique enable to tailor the microstructure of bulk magnetic products to meet specific application requirements.",

keywords = "Microstructure, MnBi, SPS",

author = "Chen, {Yu Chun} and Giuliano Gregori and Bastian Rheingans and Wenting Huang and Helmut Kronm{\"u}ller and Gisela Sch{\"u}tz and Eberhard Goering",

note = "Publisher Copyright: {\textcopyright} 2020 Elsevier B.V.",

year = "2020",

month = jul,

day = "25",

doi = "10.1016/j.jallcom.2020.154605",

language = "English",

volume = "830",

journal = "Journal of Alloys and Compounds",

issn = "0925-8388",

publisher = "Elsevier B.V.",

}

TY - JOUR

T1 - Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering

AU - Chen, Yu Chun

AU - Gregori, Giuliano

AU - Rheingans, Bastian

AU - Huang, Wenting

AU - Kronmüller, Helmut

AU - Schütz, Gisela

AU - Goering, Eberhard

PY - 2020/7/25

Y1 - 2020/7/25

N2 - In this study, we present that anisotropic MnBi bulk magnets can be obtained using spark-plasma-sintering technique (SPS). Grain misalignment was suppressed by either external field or addition of appropriate polymer binder. Various microstructures were effectively achieved during SPS processing, and lead to distinct magnetic performance. Microstructure analysis reveals that the coercive field of the SPS-compacted magnets declines strongly with increasing grain size. Bi-rich residue clearly plays a role in magnetic decoupling to enhance the coercive field, whereas the exchange coupling mediated by excess Mn reduces it dramatically. In addition, the amount and distribution of Mn and Bi residue has a profound influence on the thermal magnetic stability of sintered MnBi magnets. We suggest that fast consolidation methods like SPS technique enable to tailor the microstructure of bulk magnetic products to meet specific application requirements.

AB - In this study, we present that anisotropic MnBi bulk magnets can be obtained using spark-plasma-sintering technique (SPS). Grain misalignment was suppressed by either external field or addition of appropriate polymer binder. Various microstructures were effectively achieved during SPS processing, and lead to distinct magnetic performance. Microstructure analysis reveals that the coercive field of the SPS-compacted magnets declines strongly with increasing grain size. Bi-rich residue clearly plays a role in magnetic decoupling to enhance the coercive field, whereas the exchange coupling mediated by excess Mn reduces it dramatically. In addition, the amount and distribution of Mn and Bi residue has a profound influence on the thermal magnetic stability of sintered MnBi magnets. We suggest that fast consolidation methods like SPS technique enable to tailor the microstructure of bulk magnetic products to meet specific application requirements.

KW - Microstructure

KW - MnBi

KW - SPS

UR - http://www.scopus.com/inward/record.url?scp=85081696214&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2020.154605

DO - 10.1016/j.jallcom.2020.154605

M3 - Article

AN - SCOPUS:85081696214

SN - 0925-8388

VL - 830

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

M1 - 154605

ER -

Magnetic and microstructural properties of anisotropic MnBi magnets compacted by spark plasma sintering

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this