This book deals with the application of grazing angle x-ray and neutron scattering to the study of surface-induced critical phenomena. With the advent of even more advanced synchrotron radiation sources and new sophisticated instrumentation this novel technique is expected to experience a boom. The comprehensive and detailed presentation of theoretical and experimental aspects of the scattering of evanascent x-ray and neutron waves inside a solid makes this book particularly useful for tutorial courses. Particular emphasis is put on the use of this technique to extract microscopic information (correlation functions) from the real structure of a surface, from buried and magnetic interfaces and from surface roughness.

Owing to the increased availability of synchrotron sources, surface X-ray scattering is a rapidly expanding technique with important applications to surface structures and surface phase transitions, roughening of surfaces and interfaces, and the structure of liquid surfaces, including polymers, liquid crystals, and organic films. Surface studies with neutrons, on the other hand provide important information on liquid andmagnetic films. The contributions to this volume, written by active researchers in the field, provide an up-to-date overview of the highly sophisticated techniques and their applications.

The reflection of and neutrons from surfaces has existed as an x-rays exp- imental for almost it is in the last technique fifty Nevertheless, only years. decade that these methods have become as of enormously popular probes This the surfaces and interfaces. to be due to of several appears convergence of intense different circumstances. These include the more n- availability be measured orders tron and sources that can over (so reflectivity x-ray many of and the much weaker surface diffuse can now also be magnitude scattering of thin films and studied in some the detail); growing importance multil- basic the realization of the ers in both and technology research; important which in the of surfaces and and role roughness plays properties interfaces; the of statistical models to characterize the of finally development topology its and its characterization from on roughness, dependence growth processes The of and to surface scattering experiments. ability x-rays neutro4s study four five orders of in scale of surfaces over to magnitude length regardless their and also their to ability probe environment, temperature, pressure, etc. , makes these the choice for buried interfaces often probes preferred obtaining information about the microstructure of often in statistical a global surfaces, the local This is manner to complementary imaging microscopy techniques, of such studies in the literature witnessed the veritable by explosion published the last few Thus these lectures will useful for over a resource years.

- Up-to-date account of the principles and practice of inelastic and spectroscopic methods available at neutron and synchrotron sources - Multi-technique approach set around a central theme, rather than a monograph on one technique - Emphasis on the complementarity of neutron spectroscopy and X-ray spectroscopy which are usually treated in separate books

ways in which the magnetic interaction between neutrons and magnetic moments can yield information on the magnetization densities of thin ?lms and multilayers. I commend the organizers for having organized a group of expert lecturers to present this subject in a detailed but clear fashion, as the importance of the subject deserves. Argonne, IL S. K. Sinha Contents 1 The Interaction of X-Rays (and Neutrons) with Matter . . . . . . . . . . . . . . 1 F. de Bergevin 1. 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2 Generalities and De?nitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. 3 From the Scattering by an Object to the Propagation in a Medium . 14 1. 4 X-Rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 1. 5 X-Rays: Anisotropic Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 1. A Appendix: the Born Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . 54 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 2 Statistical Aspects of Wave Scattering at Rough Surfaces . . . . . . . . . . . . 59 A. Sentenac and J. Daillant 2. 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 2. 2 Description of Randomly Rough Surfaces . . . . . . . . . . . . . . . . . . . . . 60 2. 3 Description of a Surface Scattering Experiment, Coherence Domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 2. 4 Statistical Formulation of the Diffraction Problem . . . . . . . . . . . . . . 72 2. 5 Statistical Formulation of the Scattered Intensity Under the Born Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 3 Specular Re?ectivity from Smooth and Rough Surfaces . . . . . . . . . . . . . 85 A. Gibaud and G. Vignaud 3. 1 The Re?ected Intensity from an Ideally Flat Surface . . . . . . . . . . . . 85 3. 2 X-Ray Re?ectivity in Strati?ed Media . . . . . . . . . . . . . . . . . . . . . . . . 98 3. 3 From Dynamical to Kinematical Theory . . . . . . . . . . . . . . . . . . . . . . 107 3. 4 In?uence of the Roughness on the Matrix Coef?cients . . . . . . . . . . 111 3. A Appendix: The Treatment of Roughness in Specular Re?ectivity . . 113 3. B Appendix: Inversion of re?ectivity data . . . . . . . . . . . . . . . . . . . . . . .