This award provides partial support for the acquisition of a Microwave Network Analyzer System to support basic materials research by faculty members in the Physics, Chemistry, and Materials Science and Engineering Departments at the Pennsylvania State University. This equipment will enhance research in a number of areas including the following: (1) Dielectric nonlinearity and loss in ferroelectric thin films for tunable microwave devices; (2) characterization of high temperature superconductors by microwave penetration depth measurement to study insulator-superconductor transition by electrostatic charging; (3) study of two dimensional properties of high temperature superconductors concerning dynamics of vortex-antivortex pairs by frequency dependent measurements; (4) effects of spin injection on superconductivity in colossal magnetoresistance/high temperature superconductor multilayers; (5) single electron tunneling system produced by chemical self-assembly; (6) growth of metastable oxides by epitaxial stabilization using molecular bean epitaxy, including new artificial materials with ferroelectric and superconducting properties. Besides the four faculty members, these research projects currently involve 31 graduate students, postdoctoral fellows, and research associates. The microwave network analyzer system enables researchers to measure the magnitude, phase, and group delay of two-port networks to characterize their linear behavior from 45MHz-26.5GHz. It is a versatile system that can be used and configured for many different types of microwave measurements required by the various research projects. For example, it can be used for coplanar microstrip resonator, near-field microwave microscope, and normal metal or superconductor cavity measurements. In the proposed research, the network analyzer will be used to measure dielectric loss of ferroelectric thin films at microwave frequencies, the superfluid density in two-dimensional superconductors, and a full impedance analysis of single electron tunneling junction arrays to test quantum effects in these devices. In each of the research projects, the microwave frequency capability is crucially needed, but is not available at Penn State to these projects. The proposed network analyzer will tremendously enhance the effectiveness for the faculty members to carry out their projects and make big impact in their respective research fields. The instrument will also enhance the education activities in an NSF/CAREER project which aims to incorporate research experiences into the undergraduate curriculum by developing an experiment, Ferroelectric Thin Films, for the undergraduate laboratory course. This is part of the effort by the Physics Department at Penn State University, in particular the newly-established Center for Materials Physics, to reform physics education. Adding a microwave network analyzer to the existing facilities will expend the capability to offer students materials research experience through the undergraduate curriculum. %%% ***
