title: Critical Casimir effect in three-dimensional Ising systems: measurements on binary wetting films.
abstract: The critical Casimir force (CF) is observed in thin wetting films of a binary liquid mixture close to the liquid/vapor coexistence. X-ray reflectivity shows thickness (L) enhancement near the bulk consolute point. The extracted Casimir amplitude Delta(+-)=3+/-1 agrees with the theoretical universal value for the antisymmetric 3D Ising films. The onset of CF in the one-phase region occurs at L/xi approximately 5 regardless of whether the bulk correlation length xi is varied with temperature or composition. The shape of the Casimir scaling function depends monotonically on the dimensionality.
authors.affiliation: Department of Physics and Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA. fukuto@bnl.gov
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukuto
authors.forename: Yohko F
authors.initials: YF
authors.lastname: Yano
authors.forename: Peter S
authors.initials: PS
authors.lastname: Pershan