Year: 2019

The Wisconsin MRSEC is developing an ultrafast direct electron camera for use on a scanning transmission electron microscope (STEM) in its Shared Instrument Facilities. One application of the camera will be experiments to map strains – tiny variations in the distance between atoms – inside materials caused by defects in the crystal lattice or interfaces between two different materials. The MRSEC acquired an existing, slower camera to support technique development before the new camera arrives. An example strain map is shown to the right. The gray-scale image is a small Nb particle formed inside a larger Zr crystal. The color image shows the rotation of the Zr lattice caused by the interface between the two materials. Higher sensitivity maps covering larger areas with more points will be possible with the new camera.

Bacteria communicate via molecular signals that they produce in high concentrations. Bacterial communication promotes the formation of biofilms that can be harmful to humans and costly to industry. We have shown that collections of individual bacterial signaling molecules interact in water to form soft materials (“self-assemble”) with spherical, layered, or cylindrical structures. Simulation images showing the formation of a spherical structure (“micelle”) are shown with corresponding experimental images.

Heusler compounds are promising materials for next generation devices for direct conversion of heat to electricity (thermoelectricity) and for magnetic computer memory. Performance in these applications depends sensitively on the arrangement of the atoms and the behavior of electrons, both of which are hard to predict and harder to control for Heuslers. We have grown thin films of FeVSb, a new Heusler compound, using molecular beam epitaxy, a kind of spray painting with “cans” of different atoms. The top picture is an electron microscope image showing the arrangement of the Fe, V, and Sb as different size dots. On the right, the image shows the material we want, FeVSb. On the left, there is a completely new, unexpected material, Fe2VSb, which is a new kind of magnet.

Not all members of our community have the time or resources to attend science outreach events. To reach some of those people, the Wisconsin MRSEC conducts its engaging, hands-on science activities to a local food pantry. Customers can wait up to 90 minutes at the food pantry, providing ample time for educational activities for kids, their parents, and other curious adult visitors. By bringing science and engineering activities to the food pantry, the Wisconsin MRSEC forms connections with and helps inspire a new, diverse audience composed entirely of economically disadvantaged members of the community.

During the Wisconsin Science Festival, a statewide event that reaches over 30,000 people, the Wisconsin MRSEC developed an improvised science program held on a trolley that shuttled passengers between 27 science activities around Madison’s Capitol Square. On the trolley, an all-female team interviewed eight early career researchers about their research and lives to enable the ever-changing trolley audience to learn about the scientists and their science as well as ask their own questions of the researchers. More than 150 people rode the trolley and learned about scientific research during their journey. The event was an excellent professional development opportunity in science communication for the researchers and was covered by the Wisconsin State Journal.