Atomic Scale Analysis of Nanostructures Gregory B. Thompson, University of Alabama, DMR Intellectual Merit Ta enrichment at a triple junction grain boundary Research motivation: Atom probe tomography provides 3D reconstructions of individual atoms with near atomic spatial resolution. In order to properly interpret the data sets quantitatively, the atoms must be properly binned into 3D boxes or voxels. If the voxels are too large, spatial resolution is lost and small composition fluctuations across interfaces are not observed. If the voxels are too small, statistical error prevents confidence in the analysis. This can be seen in the different gird spacing of (A). Thus, selection of the proper binning is essential. In the present work, simulated and experimental data was analyzed to determine the influence of data binning on compositional partitioning and volume fraction. A partially crystallized, melt-spun magnetic ribbon was used as the case system, see (B). Results: A convergence of correct composition, volume fraction and ion count was found for data sets at a voxel edge length of 1.2 nm, see (C). To confirm the validity of the results, cross correlation microscopy was done. A series of dark field 2D images, (D), were compiled which yielded the approximate volume fraction of the crystallite phase which matched well to the optimized voxel size giving confidence in the technical approach. This work was presented by Karen Torres at the International Field Emission Symposium, the premier biennial atom probe meeting, held in Sydney Australia in 2010 and has been recently published – Torres et al. Ultramicroscopy Vol. 111 (2011) , giving others a guide in binning atom probe data sets. (B) (D) (C) (A)

Utilizing Research to Mentor Tomorrow’s National Technical Workforce Gregory B. Thompson, University of Alabama, DMR Broader Impact In the past reporting year, the CAREER grant provided support to Ph.D. candidates Ms. Karen Torres (Hispanic American) and Mr. Bianzhu Fu (Asian) and M.S. candidate Mr. Ross Hinson (Caucasian). Dr. Torres graduated and accepted the prestigious National Council Research Post Doctoral Fellowship at the National Institute for Standards and Technology in Maryland in Ross Hinson graduated with a MS in 2011 and has taken a position at Nucor Steel in Tennessee. Bianzhu Fu is on-track to complete his PhD during the final reporting cycle. Previously, Ms. Diondra Means (African American), partially supported by this grant, received her M.S. degree and is now employed as a Texas Instrument engineer. Professor Thompson continues to strengthen our national scientific workforce by mentoring and graduating students from historically underrepresented science and engineering demographics. During the course of the CAREER grant, Professor Thompson and students supported on this grant have actively participated in the NSF- funded program “Introducing Faculty from Historically Black Colleges (HBCU) and Universities to Materials Science and Engineering” (DMR ) each summer. Professor Thompson gives lectures on phase While at UA, the students above have ample multi- disciplinary interaction in UA’s Center for Materials for Information Technology ( The research results are disseminated to the scientific community through annual MINT Industrial Fall review. Bianzhu Fu took top honors for his poster during this meeting. transformations and incorporates returning HBCU faculty conduct research in his laboratory during the summer. Right, Bianzhu Fu assists HBCU participants in the collection of magnetic data during the summer workshop. Right, Ross Hinson prepares to describe his research at the MINT review to participants from the magnetic recording industry.