A team of researchers from the Wisconsin Materials Research Science and Education Center (MRSEC) at the University of Wisconsin–Madison has designed, constructed, and implemented a new, highly specialized piece of research equipment that can be used to visualize the real-time formation and growth of tiny crystals of novel materials. The unique perspective provided by this approach provides access to new ways to discover and develop materials relevant to electronics, optics, and magnetic applications.
Engineers currently lack good substrate materials on which to grow thin films of materials like GaN with few defects. These layers are needed in applications like high-power transistors and solid-state lighting. Available bulk crystals have the wrong crystal structure or the wrong distance between the atoms. The Wisconsin MRSEC has developed a buffer layer material and related synthesis method that promises to alleviate the substrate problem.
The Wisconsin MRSEC has created thin films of a fascinating magnetic material, Pr2Ir2O7, in which the magnetic moments are frustrated: No matter how they are arranged, some of the moments are always fighting to change their direction, like two bar magnets with their north poles shoved together. Frustration creates a rich landscape for discovery and manipulation of new magnetic effects and of electronic phenomena linked to magnetism.
Researchers at the Wisconsin MRSEC have developed a new instrument using very bright synchrotron x-ray beams to watch nanoscale crystals as they grow. The system has a unique design that allows the crystals to grow in vacuum while keeping the x-ray lenses and the x-ray beam in air but bringing them very close to the crystal. Wisconsin MRSEC researchers are using this new instrument to learn about solid phase epitaxy, a process based on the growth of ordered crystals from a disordered amorphous solid, which is capable of creating new materials for applications in electronics, optics, sensors, and quantum information.