Coordination Imperfection Suppressed Phase Stability of Ferromagnetic, Ferroelectric, and Superconductive Nanosolids

Incorporating the recent bond order−length−strength correlation mechanism [Sun; et al. J. Phys. Chem. B 2002, 106, 10701] into the Ising premise has led to consistent insight, with an analytical expression, into the Curie temperature ( T C ) suppression of ferromagnetic, ferroelectric, and superconductive nanosolids. The phase stability is related to the atomic cohesive/exchange energy that is lowered by the coordination number (CN) imperfection of the lower coordinated atoms near the surface edge. A numerical match between predictions and measurements for a number of specimens reveals that the short spin−spin correlation dominates the exchange interaction in the ferromagnetic Fe, Co, Ni, and Fe 3 O 2 nanosolids, whereas the long-range interaction dominates the exchange energy for the ferroelectric PbTiO 3, PbZrO 3, SrBi 2 Ta 2 O 9, and BaTiO 3 and the superconductive MgB 2 nanosolids.