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Title: Tuning the Magnetic Properties of New Layered Iron Chalcogenides (BaF) 2 Fe 2–x Q 3 (Q = S, Se) by Changing the Defect Concentration on the Iron Sublattice

Journal Article · · Chemistry of Materials

Effecting and controlling ferromagnetic-like properties hi senticonductors has proven to be a complex problem, especially when approaching room temperature. Here, we demonstrate the important role of defects in the magnetic properties of semiconductors by reporting the structures and properties of the iron chalcogenides (BaF)(2)Fe2-x Q(3) (Q= S, Se), which exhibit anomalous Magnetic properties that are correlated' with detects in the Fe-sublattice, The compounds form in both long-range ordered and disordered polytypes of a new structure typified by the alternate stacking of fluorite (BaF)(2)(2+) and (Fe(2-x)Q(3))(2-) layers. The latter layers exhibit an ordered array of strong Pe-Pe dimers in edge-Sharing tetrahedra. Given the strong Fe-Fe interaction, it is expected that the Fe-Fe dimer is,antiferromagnetically coupled, yet crystals exhibit a Weak ferromagnetic moment that orders at relatively-high temperature: below 280-315 K and 240275 K for the sulfide and selenide analogues, respectively. This transition temperature positively correlates with the concentration of defect in the Fe-sublattice, as determined by single-crystal X-ray diffraction. Our results indicate that internal defects in Fe(2-x)Q(3) layers play an important role in dictating the magnetic properties of newly discovered (BaF)2Fe(2),Q-3, (Q= 5-, Se), which can yield switchable ferromagnetically ordered mother-its at or above room temperature.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
DOE Contract Number:
AC02-06CH11357
OSTI ID:
1352824
Journal Information:
Chemistry of Materials, Vol. 27, Issue 9; ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English