MRI: Development of a Spin-Polarized Scanning Tunneling Microscope for Nanomagnetism Studies

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0923231de LozanneU. Texas Austin"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Technical Summary: The development of a low temperature scanning tunneling microscope with spin-polarized and spectroscopic capabilities is proposed (SP-STM). While a handful of similar instruments are operating in Europe and Japan, so far there are only two in the US. The proposed instrument will have three features that are designed to increase its productivity compared to existing facilities: the tip will be characterized with in-situ field ion microscopy, in-situ scanning electron microscopy, and with a secondary in-situ room temperature STM. The new instrument will have a superconducting magnet to provide sufficient field to manipulate the magnetic moment of the tip and the sample. This instrument will benefit the research programs of 12 faculty on our campus and will strengthen existing collaborations amongst this group and with researchers world-wide. The initial experiments will include studies of multiferroic and manganite materials. This is timely since a new MBE facility for oxide growth has just arrived. We will also study the behavior of triangular arrays of self-assembled magnetic nanoplatelets, which is a promising realization of the elusive frustrated Ising model. Spin-torque effects will be studied and used to manipulate the magnetization of individual nanoplatelets. All these studies will be complemented by existing capabilities in low temperature magnetic force microscopy and Hall Probe microscopy. The PI?s are already committed to the training of a diverse community of scientists, both individually as well as collectively through their participation in programs such as REU, IGERT, and outreach to High Schools.Layman Summary: "The nation that controls magnetism will control the universe," predicted Dick Tracy, the comic book hero debuted in 1931. The creator of this character would probably not believe to what extent this has become a reality: most of our financial, medical, and government records are now stored on magnetic media with ever increasing information density. While information storage technology has already benefitted from basic discoveries made in the past decade or two, the most recent developments are even more impressive, such as the detection of the magnetic spin of a single electron. The scanning tunneling microscope, known for its ability to image atoms on surfaces, is blind to the magnetic properties of the sample. Fortunately this microscope can be fitted with spin-polarized ?glasses? that allow us to look at the magnetic landscape at the atomic scale. Unfortunately this is not easy, and European labs have taken the lead in this important technique. Only two labs in the US have developed spin-sensitive tunneling microscopes. The PI and his group have developed similar microscopes for 27 years and propose to use their expertise to build a new generation of spin-sensitive microscopes that can make this powerful technique more widely available in the US. The team that will work on this is unusually diverse, because half of the doctoral students are female and more than half of the team is Hispanic. During the summer the team also has a few high school students, with strong emphasis on the participation of young women.