ABSTRACT
A crystal, by definition, is an infinite object; otherwise the points of its underlying lattice would not be strictly equivalent. Real crystals, however, are never infinite. We consider size effects in ferroic crystals in this chapter. Also discussed is the ferroic behaviour of polycrystals and composites, which are characterized, not only by a surface, but also by interfaces which can be of a more complex nature (e.g. due to the greater likelihood of aggregation of inclusions and pores in their vicinity) than the homophase and heterophase interfaces encountered in single-crystal ferroics.
