Rosario A. Gerhardt Professor Georgia Institute of Technology Materials Science and Engineering 771 Ferst Drive, N.W. Atlanta, GA 30332-0245 Office: Love Bldg., Room 263 Phone: 404.894.6886  | Fax: 404.894.9140 rosario.gerhardt@mse.gatech.edu Dr. Gerhardt joined the faculty of Georgia Tech as Associate Professor  in January 1991.  She was promoted to full professor in 2001.  Prior to coming to Georgia Tech she worked as an assistant research professor at the Center for Ceramics Research at Rutgers University from 1986-1990 and as a post-doctoral research associate at Rutgers for two years and at Columbia University for one year.  She also worked as an ASEE/NASA Faculty Fellow at the NASA Marshall Space Flight Center in Huntsville, AL during summer 1995. Research Interests Electromagnetic Properties Optical Properties Electroceramics Nanocomposites Non-destructive Testing Metallic Alloys, Conducting Polymers Microstructure-Property Relationships Dr. Gerhardt's research focuses on what effect microstructural factors ( such as crystal and defect structure, grain boundary, grain size, shape and phase distribution, surface adsorption and mechanical and environmental degradation) have on physical properties of all classes of materials, in particular electrical and optical properties. She has worked with a variety of dielectric insulators, ionic conductors and ceramic superconductors in bulk and thin film form, as well as conducting polymers.  Her work also extends onto non-electronics related materials such as fiber and particulate reinforced composites and metallic alloys. One of her research goals is to establish that electrical measurements can be used as a non-destructive method for microstructural characterization (click here for more details). She has been the leading organizer of a symposium series on the same subject at the Materials Research Society during the 1995, 1997 and 2001 Fall MRS Meetings.  In addition, she teaches a graduate course (MSE7140) where she covers the theory and applications of impedance spectroscopy from the microstructural point of view. Prof. Gerhardt is a Fellow of the American Ceramic Society and a member of the International Microelectronics and Packaging Society, the Materials Research Society,  the IEEE/Dielectrics Division, the Metallurgical Society, and the Microscopy Society of America.  She is also a member of Sigma Xi, Keramos and Tau Beta Pi . She has been active as an executive officer of the Electronics Division of the American Ceramic Society for the last ten years, having served as Chair of that division during the 2000-2001 year.   She also serves as the Faculty Advisor for the Student Chapter of the American Ceramic Society at Georgia Tech and has been co-organizer of numerous symposia both at ACerS as well as MRS. She is the author or co-author of over 100 refereed publications and the editor of three MRS symposium proceedings books (vols. 411, 500 and 699).    Current Research Projects Electrical  Properties of Insulator-Conductor Composites Impedance Spectroscopy of Nickel Base Superalloys Thin Films for Microelectronic Applications Structure-Property Relationships in Conducting Polymers Electrochemical Characterization of Biomedical Implant Materials (papers in preparation) General Papers R. Gerhardt, "Dielectric and Impedance Spectroscopy Revisited:  Distinguishing Localized Relaxation from Long Range Conductivity,"  J. Phys. Chem. Solids. 55[12]  1491-1506 (1994). R.A. Gerhardt and W. Cao, “Distinguishing bulk water from adsorbed water via dielectric measurements, ”IEEE Proc. CEIDP, 102-105(1996). H.M. Kerch, G.G. Long, S. Krueger, R.A. Gerhardt and F. Cosandey,  “Characterization of Porosity at All Length Scales:  Application  to Colloidal Gels,” J.Mat.Res. 14[4], 1444-1454 (1999). R.A. Gerhardt, “Electrically Based Non-Destructive Microstructural Characterization of All Classes of Materials,” Mat.Res.Symp.Proc. 591, 93-104 (2000). INSULATOR-CONDUCTOR PAPERS J.Runyan, R.A. Gerhardt and R. Ruh, “Electrical Properties of BN Matrix Composites – Part I: Analysis of the McLachlan Equation in Modeling the Conductivity of BN-B4C and BN-SiC Composites”, J.Am.Ceram.Soc 84[7], 1490-1496(2001). J.Runyan, R.A. Gerhardt and R. Ruh, “Electrical Properties of BN Matrix Composites – Part II: Dielectric Relaxations in Boron Nitride- Silicon Carbide Composites,” J.Am.Ceram.Soc 84[7] , 1497-1503 (2001). R.A. Gerhardt, J. Runyan, C. Sana, D.S. McLachlan and R. Ruh, “Electrical Properties of BN Matrix Composites – Part III: Observations Near Percolation Threshold in BN-B4C Composites”,  J.Am.Ceram.Soc 84[10] 2335-2342(2001). R.A. Gerhardt and R. Ruh, “Volume Fraction and Whisker Orientation Dependence of the Electrical Properties of SiC Whisker Reinforced Mullite Composites,” J. Am.Ceram.Soc. 84[10],2328-2334(2001). R. Ou, R.A. Gerhardt, C. Marrett, A. Moulart and J.S. Colton, “Assessment of Percolation and Homogeneity in ABS/CB Composites by Electrical Measurements,” Composites Part B: Engineering 34[7], 607-614(2003). THIN FILMS FOR MICROELECTRONICS Y. Kim, R.A. Gerhardt and A. Erbil, “Dynamical Properties of Epitaxial Ferroelectric Heterostructures,” Phys.Rev.B.55, 4477-4485 (1997-II)., Z. Mustapha, S-W Chan, A. Lam and R.A. Gerhardt, “Accuracy of Energy Dispersive X-Ray Composition Analysis of YBCO on Yttrium Containing substrates,” J.Mat.Sc. 35[2].443-453(2000). D.W. Riley and R.A. Gerhardt, “Microstructure and Optical Properties of Submicron  Porous Silicon Thin Films Grown at Low Current Densities,” J.Appl.Phys. 87[5], 2169-2177 (2000). H.X. Qin, R.A. Gerhardt and J.S. Zhu, “Doping Effects on the Properties and Microstructure of Intergrowth Bi4Ti3O12 – SrBi4Ti4O15 Thin Films,” Integrated Ferroelectrics 45, 183-188(2002). METALLIC ALLOYS R.A. Gerhardt, J.R. Kokan, D.J. Roth, B.A. Lerch and B. Lawless, “A Novel Technique for Detecting Microstructural Changes in Aged Ni-Base Alloys,” Proceedings of the NASA HitempConf. Vol. 2, 325-345 (1999). R.A. Gerhardt, B. Lawless and D.J. Roth, “Impedance Spectroscopy of Waspaloy as a function of Thermal Exposure,” 3rd FAA/DOD/NASA Conference on Aging Aircraft, 1-14 (1999). K. Pinkos, C. Laboy and R.A. Gerhardt, “Effect of Grain Boundaries and Indentation Load on the Electrical Properties ofNickel Base Superalloys,” Mat.Res.Symp.Proc. 699, 289-294(2002). X. Zou, T. Makram and R.A. Gerhardt, “Detection of Compositional Fluctuations in Waspaloy Exposed to High Temperatures,” Mat.Res.Symp.Proc. 699, 301-306(2002). CONDUCTING POLYMERS Runqing Ou, Robert Samuels and R. A. Gerhardt, “In-plane Impedance Spectroscopy of Doped Polyaniline Films,” J.Plastic Films and Sheeting,17[4],184-196(2001). R. Ou, R. Samuels and R.A. Gerhardt, “The Structure and Electrical Properties of Polyaniline,” Mat.Res.Symp.Proc. 699, 333-338(2002). R.A. Gerhardt, R. Ou, J. Colton, C. Marrett and A. Moulart, “Assessment of Percolation and Homogeneity in ABS/Carbon Black Composites,” Ninth International Conference on Composites Engineering, Proc. ICCE/9, 231 (2002). R. Ou, R. Samuels and R.A. Gerhardt, “A Structure-Electrical Property Study of Anisotropic Polyaniline Films,” J.Poly.Sc.: Pol.Phys. 41:823-841(2003). 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