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n addition to the National Center for Electron Microscopy (NCEM), and several beamlines at the Advanced Light Source (ALS) tailored specifically for use by researchers in the materials and chemical sciences, Berkeley Lab has been selected to create and host a Molecular Design Institute (MDI) on the West Coast. (There will also be one on the East Coast in Atlanta.) The purpose of this institute is to combine the efforts of chemists, biochemists, and physicists for the atomic-scale design, synthesis, processing, and characterization of new molecules and materials. Potential areas of application will include electronics, photonics, sensors, catalysts, and a wide variety of novel materials and coatings. The Berkeley Lab will establish its MDI in collaboration with five universities (including UC Berkeley and UCLA) and four companies from private industry. Research is already under way at the MDI with first-year results that made the cover of Science magazine. First, Berkeley Lab scientists at the institute announced that they had found a way to deposit thousands of distinct combinations of metal-oxide molecules onto an area the size of a checkerboard square, thereby creating the first "combinatorial" library of advanced materials. By increasing the number of compounds that can be created and tested as potential new materials from about one a day to as many as 10,000 a day, this new technique, called "combinatorial synthesis," promised to speed the pace of discovery in materials science. This promise was vividly realized within four months of the first announcement, when the same team of Berkeley Lab scientists announced the discovery of a new family of magnetoresistive (MR) compounds, materials whose electrical conductivity changes in a magnetic field.

In recent years, new advanced materials have usually been discovered through the substitution or altering of the ratio of atoms in a known compound (sometimes based on the predictions of computer models). With combinatorial synthesis, in which thousands of distinct combinations of molecules are deposited onto a square grid the size of a checkerboard square, scientists can look at many atom substitutions and ratio adjustments in a single combinatorial library. To look for new materials with magnetoresistance, Berkeley Lab scientists started with a well-studied class of MR materials based on manganese oxide, substituted similar elements from the periodic table (iron, vanadium and cobalt) for manganese, and made a separate combinatorial library for each one. Their cobalt oxide library yielded 26 new materials that displayed magnetoresistance comparable to the so-called "colossal" class of magnetoresistance materials.

Because colossal magnetoresistant materials (CMR) become superconducting in the presence of a sufficiently strong magnetic field, thin films of these materials are in great demand by the electronics industry. Currently, these materials are limited to laboratory studies, where they are made through a costly technique called pulsed laser ablation. The situation may soon change, however. Berkeley Lab scientists at NCEM this past year unveiled a relatively inexpensive chemical process for making CMR thin films out of the same class of ceramic materials that exhibit high-temperature superconductivity. At a fraction of the cost of pulsed laser ablation, this new process holds potential for commercial as well as scientific applications. Upon viewing their new thin films through the powerful transmission electron microscopes at NCEM, the Berkeley Lab scientists found they could easily vary the composition and structure in order to make a variety of different products, including multilayer films with alternating magnetic layers.

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