Synthesis of Ideal Iron Film Samples for Shock Physics Experiments Using Ultrafast X-Ray Diffraction

Abstract

The fabrication of iron (Fe) films epitaxially grown on single crystal magnesium oxide (MgO) substrates is presented. Our goal is the creation of ideal crystalline iron samples for shock physics experiments using ultrafast x‐ray diffraction. There are several reasons for the choice of the Fe/MgO system. Iron is known to undergo shock‐induced structural changes, and MgO is selected because it is a) transparent to the laser light used to generate the shock in the Fe film and b) there is only a 4% lattice mismatch between Fe and MgO. Issues such as generating a specific crystallographic orientation in the iron film and technical challenges in the synthetic process are discussed. The ultimate goal for producing a single crystal Fe film on MgO is to allow the merger of theory and experiment. A new ultrafast x‐ray diffraction experiment will permit the detection of laser‐driven shock‐induced phase changes in the crystalline Fe samples. These experiments will complement an elegant MD investigation of a shocked Fe crystal.p.