MnBi particles with high energy density made by spark erosion

Journal Article · Wed May 07 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4868330· OSTI ID:1211334

Nguyen, PK; Jin, SH; Berkowitz, AE

We report on the properties of low-temperature phase (LTP)-MnBi particles produced by the rapid-quenching technique of spark-erosion. The as-prepared powder consists of amorphous, crystalline, and superparamagnetic particles, mostly as porous aggregates. The major fraction of the powder consists of 20-30 nm particles. A short anneal crystallizes the amorphous particles producing a high moment, >90% of theoretical M-S, albeit with H-C of a few kOe. If lightly milled, the agglomerates are broken up to yield H-C of 1 T. These findings are supported by the x-ray diffraction pattern showing broadened peaks of the predominant LTP-MnBi phase. The combination of spark erosion, milling, and annealing has produced randomly oriented particles with (BH)(MAX) similar to 3.0 MGOe. The particles are expected to show record energy product when aligned along their crystallographic easy axes. (C) 2014 AIP Publishing LLC.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• OSTI ID: 1211334
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 115; ISSN 0021-8979
• Country of Publication: United States
• Language: English