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Hysteresis properties of sized dispersed monoclinic pyrrhotite grains
Author(s) -
Clark D. A.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i003p00173
Subject(s) - pyrrhotite , coercivity , monoclinic crystal system , grain size , materials science , hysteresis , superstructure , mineralogy , geology , crystallography , condensed matter physics , crystal structure , composite material , chemistry , pyrite , physics , oceanography
Monoclinic pyrrhotite (Fe 7 S 8 with 4C superstructure) was magnetically separated from a massive pyrrhotitic ore for preparation of nine grain‐size fractions ranging from ∼ 80 µm (large multidomain grains) to < 3 µm (single‐domain grains). Grains smaller than 100 µm were found to be magnetically hard with coercive forces ranging from 135 oe for 83 µ grains to 920 oe for < 3 µm grains. For grain sizes between 83 µm and 7 µm the coercive force is given by H c ⧜ d −0.79 . Variations in hysteresis properties with grain size appear to be gradual, with no evidence of sudden changes associated with domain structure transitions.