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 Fe3O2 nanosolids, whereas the long-range interaction dominates the exchange energy for the ferroelectric PbTiO3, PbZrO3, SrBi2Ta2O9, and BaTiO3 and the superconductive MgB2 nanosolids.