Anisotropy in magnetic properties of single crystal LiFePO$_{4}$

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 $J_{2})$, inter-plane spin-exchange ($J_{\bot })$, 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.