Anisotropy in magnetic properties and electronic structure of single-crystal LiFePO(4)

作者：Liang Gan^*; Park Keeseong; Li Jiying; Benson Ronald E; Vaknin David; Markert John T; Croft Mark C

来源：Physical Review B, 2008, 77(6): 064414.

DOI：10.1103/PhysRevB.77.064414

We report the experimental and theoretical results on the anisotropies in the magnetic properties and x-ray absorption spectra of single-crystal LiFePO(4). A mean-field theory is developed to explain the observed strong anisotropies in Lande g-factor, paramagnetic Curie temperature, and effective moment for LiFePO(4) single crystals. The values of the in-plane nearest- and next-nearest-neighbor spin exchange (J(1) and J(2)), interplane spin exchange (J(perpendicular to)), and single-ion anisotropy (D), obtained recently from neutron scattering measurements, are used for calculating the Curie temperatures with the formulas derived from the mean-field Hamiltonian. It is found that the calculated Curie temperatures match well with that obtained by fitting the magnetic susceptibility curves to the modified Curie-Weiss law. For the polarized Fe K-edge x-ray absorption spectra of single-crystal LiFePO(4), a different feature assignment for the 1s -> 4p transition features is proposed and the anisotropy in the intensities of the 1s -> 3d transition features is explained adequately by a one-electron theory calculation of the electric quadrupole transition terms in the absorption coefficient.

• 出版日期2008-2