CAREER: The Laboratory Experience: Introductory Physics through Independent Research

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Zieve 9733898 This is a CAREER Award to a female scientist and is composed of two subprojects. One component employs the controlled introduction of structural defects to modify the phase diagram and vortex behavior of the superconducting heavy fermion system (U,Th)Be13. This system exhibits multiple superconducting phases, as well as magnetism, and should provide clues to understanding other unconventional superconductors, such as the high-Tc superconductors. Columnar defects will be created through heavy- ion irradiation, and point defects through both irradiation and substitution. Low-temperature thermodynamic and magnetic measurements will be used to identify the superconducting wave function(s) of the system. The educational component involves facilitating undergraduate research through a less technically demanding set of experiments. These involve the study of packing arrangements of solid objects. Vibrating a container of beads anneals them into the densest possible arrangement in two dimensions, but not in three dimensions. This project will examine the dimensional crossover by varying container size and shape, and will test different annealing procedures to determine the interaction of dimensionality and dynamical processes. %%% This a CAREER Award to a female scientist and is composed of two subprojects. One component investigates materials known as "heavy fermion" superconductors. These superconductors carry electric current with no energy loss, like ordinary superconductors, but in addition exhibit unusual magnetic behavior. Structural imperfections of the atoms in the sample will be deliberately introduced in order to modify their electrical and magnetic properties. The resulting changes in the onset temperature of superconductivity and the magnetic behavior of the superconductor are expected to shed light on the atomic origins of the superconductivity. This could lead to new superconducting materials and a better understanding of superconductors in practical applications. The educational component will introduce undergraduates to research through a less technically demanding set of experiments. These experiments involve studies of how objects arrange themselves in two and three dimensions. Shaking solid objects, such as glass beads, causes them to pack in the densest way possible if the objects are constrained to a single layer. However, this does not occur if they are stacked in three dimensions, as in a jar of coffee beans. To understand the transition from two-dimensional to three-dimensional behavior, arrangements of objects only a few layers thick will be studied. The general problem of packing is relevant to the fabrication of new composite materials, where high density components often impart special properties to the overall material. Technical abstract