The structural and electrical properties of epitaxial Pb͑Zr 0.2 Ti 0.8 ͒O 3 thin films grown on 2 in. ͑001͒ silicon wafers were investigated. Using x-ray diffraction, the lattice behavior of the heterostructure has been studied as a function of temperature, suggesting a 250°C increase of the Pb͑Zr 0.2 Ti 0.8 ͒O 3 ferroelectric-paraelectric transition temperature with respect to the bulk value. This significant enhancement of the critical temperature is understood in terms of a two-dimensional clamping effect.