In her National Science Foundation grant in collaboration with WVU theorist Tudor Stanescu and North Carolina State University’s James LeBeau, they will study why magnetic oxide thin films lose their magnetism when they become thin or even at their surfaces and other interfaces. This loss of magnetism can be a significant detriment to various applications.
Understanding the physics behind this effect would allow not only to reverse the negative effect, but also to manipulate the physics to predict and control systems where the surface or bulk magnetism can be enhanced. Such understanding of surface physics may have implications well beyond the field of magnetic materials. In her Department of Energy grant in collaboration with WVU theorist Aldo Romero, they will investigate the effect of an adjacent ferroelectric layer on the oxygen vacancies (missing oxygen) in magnetic films and the resulting effect on material properties. Oxygen vacancies are known to have dramatic effects on material properties, yet they are rarely measured due to the difficulty of these measurements. The use of nondestructive synchrotron methods will be explored to not only quantify these vacancies and their effects, but also to map out how they move through the sample due to ferroelectric poling. In a grant from the American Chemical Society, Holcomb is exploring ultrafast optical measurements to relate the ultrafast dynamics to the bulk and surface magnetization of a variety of magnetic oxides, some of which are abundant in the Earth’s crust (meaning potentially cheap to manufacture) and have been understudied. To investigate these projects, the Holcomb team employs a variety of techniques. They start with high quality films grown by a process called pulsed laser deposition. In addition to the standard characterization methods traditionally utilized to assess sample quality, they also specialize in unique experimental tools, including ultrafast optical and synchrotron radiation techniques.