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Anisotropy-induced spin disorder in intergrown, ferrimagnetic Fe$_7$ S$_8$ polytypes

Firlus, Alexander ; Schawe, Jürgen E. K.; Weidler, Peter G. 1; Charilaou, Michalis; Löffler, Jörg F.; Gehring, Andreas U.
1 Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT)

Abstract:

The monosulfides of the pyrrhotite omission series (Fe$_{1−𝑥}$S, 0<𝑥≤0.125) are important remanence carriers for paleomagnetic reconstruction of the Earth's crust and extraterrestrial materials. The ferrimagnetic Fe$_7$S$_8$ polytypes are the endmembers, and their stacking modulations of full and vacant layers generate different magnetic anisotropy properties due to the cation-vacancy configurations. In this study, intergrown long-range ordered polytypes with four- and threefold modulation, i.e., 4C and 3C pyrrhotite, were prepared in a diffusion-driven process by quenching of a natural pyrrhotite crystal with randomized vacancies. In addition, a third constituent with coherence lengths of a few nanometers, denoted 3C*, was found that exhibits spin-glass behavior at about 10 K due to local magnetic anisotropies arising from vacancy-density variations. The concomitant occurrence of this nano-scale constituent with spin disorder and the long-range ordered polytypes indicate competitive diffusion-driven processes during Fe$_7$S$_8$ formation. Such information provides insight into the provenance and genesis of ferrimagnetic pyrrhotite in Earth and extraterrestrial systems and in a broader sense into vacancy-induced materials.


Verlagsausgabe §
DOI: 10.5445/IR/1000152292
Veröffentlicht am 07.11.2022
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Funktionelle Grenzflächen (IFG)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2022
Sprache Englisch
Identifikator ISSN: 0003-6951, 1077-3118
KITopen-ID: 1000152292
HGF-Programm 43.33.11 (POF IV, LK 01) Adaptive and Bioinstructive Materials Systems
Erschienen in Applied Physics Letters
Verlag American Institute of Physics (AIP)
Band 121
Heft 15
Seiten Art.-Nr.: 154103
Vorab online veröffentlicht am 11.10.2022
Schlagwörter Complex solids, X-ray diffraction, Minerals, Magnetic anisotropy
Nachgewiesen in Scopus
Web of Science
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