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Title: MnBi particles with high energy density made by spark erosion

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.
Authors:
;  [1] ;  [2] ;  [3] ;  [2]
  1. Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093 (United States)
  2. (United States)
  3. Physics Department, University of California, San Diego, La Jolla, California 92093 (United States)
Publication Date:
OSTI Identifier:
22280508
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; 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