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Title: LiFe{sub 2}Cl{sub n} (n = 4–6) clusters: Double-exchange mediated molecular magnets

A systematic study of LiFe{sub 2}Cl{sub n} (n = 4–6) clusters, based on gradient corrected density functional theory (DFT), shows that the electron contributed by Li can transform antiferromagnetic Fe{sub 2}Cl{sub n} (n = 4 and 6) clusters into ferromagnetic clusters. In Fe{sub 2}Cl{sub 6} (Fe{sub 2}Cl{sub 4}) cluster, the Fe atoms in +3 (+2) oxidation states are aligned antiferromagnetically, consistent with the super-exchange model. The extra electron from Li atom creates a charge disproportionation in the LiFe{sub 2}Cl{sub 6} (LiFe{sub 2}Cl{sub 4}) cluster that mediates the double-exchange interaction between the Fe atoms. Antiferromagnetic to ferromagnetic transition can also be induced by hole doping as seen to be the case with Fe{sub 2}Cl{sub 5} which has a ferromagnetic ground state. Simultaneous electron and hole doping is also seen to impact on the magnetic properties of LiFe{sub 2}Cl{sub 5} which can be viewed as (Fe{sub 2}Cl{sub 4}+LiCl). While Fe{sub 2}Cl{sub 4} is antiferromagnetic and LiCl is nonmagnetic, the ground state of LiFe{sub 2}Cl{sub 5} is ferromagnetic. We also analyzed the results with on-site Coulomb interaction U by performing DFT+U calculations. These results can be useful in the synthesis of functional molecular magnets.
Authors:
;  [1]
  1. Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)
Publication Date:
OSTI Identifier:
22350983
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 16; 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; ANTIFERROMAGNETISM; COMPUTERIZED SIMULATION; DENSITY FUNCTIONAL METHOD; ELECTRONS; EXCHANGE INTERACTIONS; GROUND STATES; IRON CHLORIDES; LITHIUM CHLORIDES; MAGNETIC PROPERTIES; MAGNETS; MOLECULAR CLUSTERS; OXIDATION; SYNTHESIS