Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (01): 107-112.doi: 10.3866/PKU.WHXB20090119

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Electronic Structures of New Half-Metal Material CrFe2O4

LIU Jun; LIU Yu; CHEN Xi-Ming; DONG Hui-Ning   

  1. Institute of Applied Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065, P. R. China; College of Physics and Mathematics, Chongqing University, Chongqing 400044, P. R. China
  • Received:2008-07-24 Revised:2008-10-05 Published:2008-12-31
  • Contact: LIU Jun E-mail:liujun@cqupt.edu.cn

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Abstract: Geometric structures of cubic spinel materials (CrxFe1-x)A(CryFe2-y)BO4 were optimized and their magnetic and electric properties were calculated using the first principles. Electronic structures and the micromechanism of half-metallicity of CrFe2O4 were analyzed based on coordinate field theory. From our calculation, it is showed that (CrxFe1-x)A(CryFe2-y)BO4 has half-metallicity only when x=1.0 and y=0.0. CrFe2O4 is a type of ferrimagnetic IIB-type half-metal material and its molecular magnetic moments are about 5.6 μB which is higher than the 4.0 μB of Fe3O4. Electronic structures of Cr-ions can be approximately written as Cr+t12g↑t32g↓ and those of Fe-ions can be approximately written as Fe2+t32g↑e2g↑t12g↓. The micromechanism of the half-metallicity of CrFe2O4 is concerned with the strong covalent interaction in the coordinate compounds ML4 and ML6. Mixed orbits between central ions and their ligand result in separated up-spin sub-bands and the Fermi level lies in the gaps of up-spin sub-bands.

Key words: Spintronics, Half-metal, CrFe2O4, Molecular magnetic moments