We present a first-principles investigation of the structural, magnetic, and electronic properties of $\mathrm{Li}\mathrm{Fe}\mathrm{P}{\mathrm{O}}_4$ olivine. The ground-state antiferromagnetic spin arrangement consistent with a superexchange mechanism through oxygen orbits is found to be preferred, showing an antiferromagnetic order between corner sharing octahedra along the [010] direction. This is in agreement with an oxygen-mediated superexchange mechanism for the iron-iron magnetic interaction. The theoretical Néel temperature estimated by a mean-field approximation is in the range between $33.1\mathrm{K}$ and $53.5\mathrm{K}$, in acceptable agreement with the experimental susceptibility measurement, which gives $T_{\mathrm{N}}=52\mathrm{K}$. The calculated magnetic moment of $3.72{\mu }_{\mathrm{B}}$ is close to the value of $4{\mu }_{\mathrm{B}}$ deduced from the ionic model according to the Hund’s rule.

• Received 29 June 2004

DOI:https://doi.org/10.1103/PhysRevB.71.144404