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On the Magnetism Behind the Besnus Transition in Monoclinic Pyrrhotite
Author(s) -
Koulialias Dimitrios,
Schäublin Robin,
Kurtuldu Güven,
Weidler Peter G.,
Löffler Jörg F.,
Gehring Andreas U.
Publication year - 2018
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2018jb015548
Subject(s) - pyrrhotite , remanence , ferrimagnetism , rock magnetism , magnetism , magnetization , vacancy defect , condensed matter physics , monoclinic crystal system , geology , phase transition , materials science , mineralogy , crystallography , chemistry , crystal structure , physics , magnetic field , pyrite , quantum mechanics
In monoclinic 4C pyrrhotite (ideal formula Fe 7 S 8 ), ordered vacancy distribution forms a superstructure with strong ferrimagnetism that makes this mineral a major remanent magnetization carrier in the Earth's crust. The pronounced decrease in isothermal remanence magnetization at about 32 K, known as Besnus transition, is a characteristic trait that marks the low‐temperature transition in 4C pyrrhotite, and it is used as a key to identify this mineral phase in rock samples. Here we take a nearly pure single pyrrhotite crystal (Fe 6.97 S 8 ) from the Swiss Alps to study its Besnus transition in a broad mineral‐magnetic approach that combines detailed structural analysis with static and dynamic magnetization experiments. All the magnetic properties inferred from the experimental data are discussed in the context of a recent model that explains interacting anisotropy fields in the 4C pyrrhotite caused by the vacancy arrangement as the origin of the Besnus transition.