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:22280508

Nguyen, Phi-Khanh; Jin, Sungho ^[1]; Berkowitz, Ami E. ^[2]

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1. Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093 (United States)
2. Physics Department, University of California, San Diego, La Jolla, California 92093 (United States)

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{sub S}, albeit with H{sub C} of a few kOe. If lightly milled, the agglomerates are broken up to yield H{sub 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){sub MAX} ∼ 3.0 MGOe. The particles are expected to show record energy product when aligned along their crystallographic easy axes.

• OSTI ID: 22280508
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 115; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
BISMUTH
ENERGY DENSITY
EROSION
INTERMETALLIC COMPOUNDS
MAGNETIC MATERIALS
MANGANESE
MILLING
NANOSTRUCTURES
PARTICLE SIZE
PARTICLES
POROUS MATERIALS
POWDERS
QUENCHING
SUPERPARAMAGNETISM
X-RAY DIFFRACTION