For a long time, secondary ion mass spectrometry (SIMS) was the only technique allowing impurity concentrations below 1 at% to be precisely measured in a sample with a depth resolution of few nanometers. For example, SIMS is the classical technique used in microelectronics to study dopant distribution in semiconductors and became, after radiotracers were forsaken, the principal tool used for atomic transport characterization (diffusion coefficient measurements). Due to the lack of other equivalent techniques, sometimes SIMS could be used erroneously, especially when the analyzed solute atoms formed clusters, or for interfacial concentration measurements (segregation coefficient measurements) for example. Today, concentration profiles measured by atom probe tomography (APT) can be compared to SIMS profiles and allow the accuracy of SIMS measurements to be better evaluated. However, APT measurements can also carry artifacts and limitations that can be investigated by SIMS. After a summary of SIMS and APT measurement advantages and disadvantages, the complementarity of these two techniques is discussed, particularly in the case of experiments aiming to measure diffusion and segregation coefficients.

The following article is based on the MRS Medal talk by Norm Bartelt (Sandia National Laboratories, California), presented at the 2001 Materials Research Society Fall Meeting on November 29 in Boston. Bartelt received the Medal for his “contributions to the statistical mechanics of materials surfaces.” A long-standing goal of materials science research has been to predict the long-term evolution of the microstructure of materials from a knowledge of atomic processes. This is usually extremely difficult to do in any detail because of the large number of atomic processes to consider, many of which are poorly understood. On solid surfaces, however, progress in the prediction of microstructural evolution can now be made because of advances in real-time microscopy that allow the characterization of the time evolution of microstructure in unprecedented detail. These observations directly reveal the complex relationships between collective thermal fluctuations on atomic scales and deterministic behavior on macroscopic scales. In this presentation, attempts to construct models of these observations are discussed.

The martensitic transformation has so far been studied without considering its interaction with point defects. In this article, we shall show that such interaction, which stems from a universal symmetry property of point defects, can create a rich spectrum of exotic multiscale phenomena in martensitic materials. These phenomena include unique short-range diffusion at the atomic or nano level, remarkable domain-pattern memory at the mesoscopic level, and peculiar rubber-like behavior and aging-induced two-way shape memory at the macroscopic level. Exotic multiscale phenomena may also be found in a wide range of transforming materials, such as ferroelastic, ferroelectric, and ferromagnetic materials. These novel effects may provide new opportunities for these important materials.