  The finite-size effect on the antiferromagnetic (AF) transition and
electronic configuration of iron has been observed in LiFePO4. Determination of
the scaling behavior of the AF transition temperature (TN) versus the
particle-size dimension (L) in the critical regime 1-TN(L)/TN(XTL)\simL^-1
reveals that the activation nature of the AF ordering strongly depends on the
surface energy. In addition, the effective magnetic moment that reflects the
electronic configuration of iron in LiFePO4 is found to be sensitive to the
particle size. An alternative structural view based on the polyatomic ion
groups of (PO4)3- is proposed.
