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Angus P. WilkinsonProfessor Office: 1100J Phone: 404-894-4036 Fax: 404-894-7452 |
B.A., Oxford University, 1988; D. Phil, Oxford University, 1992
NSF CAREER Award - 1996; Sigma Xi award for outstanding research by a junior faculty member - 1996
Research Interests
Negative Thermal Expansion (NTE) Materials. Most materials expand as they are heated, but there is a small and growing group of compounds that shrink on heating (display negative thermal expansion). Such materials are of potential use in composites as blending both negative and positive thermal expansion compounds provides a way of tailoring the thermal expansion characteristics of the resulting material. Being able to tailor the thermal expansion characteristics is useful as there are many applications where either zero thermal expansion is desirable (e.g. optical devices where accurate positioning is crucial) or there is a need to match the thermal expansion coefficients of two parts that are bonded together. We have developed a synthetic method for the preparation of a new NTE material cubic ZrMo2O8and we are currently investigating both the details of its physical properties and methods for tailoring the thermal expansion characteristics of this material and some of its relatives.
Clathrate Thermoelectric Materials. Thermoelectric devices can be used to provide electrical power from a temperature difference or to produce a temperature difference when supplied with electrical power. There is considerable interest in developing new materials that would facilitate the replacement of current refrigeration technology with efficient all solid-state thermoelectric devices. One attractive candidate family of materials are the so called clathrates. They have 3-D covalently bonded frameworks of atoms such as Si, Ge, or Sn with species such as Cs, Rb, K, Na, Sr, or Eu vibrating inside cavities in the framework. The disorder associated with the vibrational motion of the species in the cavities and any disorder in the framework that is introduced by doping has a large impact on their thermoelectric properties. We are currently exploring the occurrence and importance of disorder in clathrate thermoelectric materials in collaboration with researchers at Renslaer Polytechnic Institute and Marlow Industries.
New Applications of Synchrotron X-ray Methods. We are interested in further developing the use of synchrotron X-ray diffraction methods for the characterization of materials. The extremely high intensity and high-energy X-ray beams that are available from third generation synchrotron sources provide unique opportunities for examining materials. We are currently working with faculty from the materials science and civil engineering programs at Georgia Tech to develop methods for the non-destructive evaluation of corrosion in concrete and related systems.
Representative Publications
Heat capacity, lattice dynamics, and thermodynamic stability of the negative thermal expansion material HfMo2O8, Kennedy, Catherine A.; White, Mary Anne; Wilkinson, Angus P.; Varga, Tamas, Physical Review B: Condensed Matter and Materials Physics 75(22), 224302/1-224302/9, (2007).
Low thermal conductivity of the negative thermal expansion material, HfMo2O8, Kennedy, Catherine A.; White, Mary Anne; Wilkinson, Angus P.; Varga, Tamas, Applied Physics Letters 90(15), 151906/1-151906/3, (2007).
High-pressure powder diffraction study of TaO2F, Cetinkol, Mehmet; Wilkinson, Angus P.; Lind, Cora; Bassett, William A.; Zha, Chang-Sheng, Journal of Physics and Chemistry of Solids 68(4), 611-616, (2007).
Preparation and characterization of In(I)-β-alumina, Cetinkol, M.; Lee, P. L.; Wilkinson, A. P.. Materials Research Bulletin 42(4), 713-719, (2007).
Heats of Formation for Several Crystalline Polymorphs and Pressure-Induced Amorphous Forms of AMo2O8 (A = Zr, Hf) and ZrW2O8, Varga, Tamas; Lind, Cora; Wilkinson, Angus P.; Xu, Hongwu; Lesher, Charles E.; Navrotsky, Alexandra, Chemistry of Materials 19(3), 468-476, (2007).
Pressure-induced amorphization of cubic ZrW2O8 studied in situ and ex situ by synchrotron x-ray diffraction and absorption. [Erratum to document cited in CA143:315762], Varga, Tamas; Wilkinson, Angus P.; Jupe, Andrew C.; Lind, Cora; Bassett, William A.; Zha, Chang-Sheng. Physical Review B: Condensed Matter and Materials Physics 74(21), 219902/1, (2006).
Multi-mode X-ray study of sodium and magnesium sulfate attack on portland cement paste, Naik, N. N.; Jupe, A. C.; Stock, S. R.; Wilkinson, A. P.; Lee, P. L.; Kurtis, K. E., Advances in X-Ray Analysis 49, 63-72, (2006).
Sample cell for powder x-ray diffraction at up to 500 bars and 200 °C, Jupe, Andrew C.; Wilkinson, Angus P., Review of Scientific Instruments 77(11), 113901/1-113901/4, (2006).
Neutron powder diffraction study of the orthorhombic to monoclinic transition in Sc2W3O12 on compression, Varga, Tamas; Wilkinson, Angus P.; Jorgensen, James D.; Short, Simine, Solid State Sciences 8(3-4), 289-295, (2006).
Sulfate attack monitored by microCT and EDXRD: Influence of cement type, water-to-cement ratio, and aggregate, Naik, N. N.; Jupe, A. C.; Stock, S. R.; Wilkinson, A. P.; Lee, P. L.; Kurtis, K. E., Cement and Concrete Research 36(1), 144-159, (2006).
High pressure synchrotron x-ray powder diffraction study of Sc2Mo3O12 and Al2W3O12, T. Varga, A. P. Wilkinson, C. Lind, W. A. Bassett, C. -S. Zha, J. Phys.: Condens. Matter, 17, 4271-4283 (2005).
In situ high-pressure synchrotron x-ray diffraction study of Sc2Mo3O12 to 10 GPa, T. Varga, A. P. Wilkinson, C. Lind, W. A. Bassett, C.-S. Zha, Phys. Rev. B, 71, 214106 (2005).
Negative thermal expansion in cubic ZrMo2O8: Inelastic neutron scattering and lattice dynamical studies, R. Mittal, S. L. Chaplot, H. Schobes, A. I. Kolesnikov, C. -K. Loong, C. Lind and A. P. Wilkinson, Phys. Rev. B 70, 214303 (2004).
Phase Composition Depth Profiles using Spatially Resolved EDXRD, A. C. Jupe, S. R. Stock, P. L. Lee, N. Naik, K. E. Kurtis, and A. P. Wilkinson, J. Appl. Crystallogr. 37, 967-976 (2004).
Fluorinert as a pressure-transmitting medium for high pressure diffraction studies, T. Varga, A. P. Wilkinson, R. J. Angel, Rev. Sci. Inst., 74, 4564-4566, (2003).
Gallium Distribution in the Clathrates Sr8Ga16Ge30 and Sr4Eu4Ga16Ge30 by Resonant Diffraction, Y. Zhang, G. S. Nolas, P. L. Lee and A. P. Wilkinson, Appl. Phys. Lett. 80, 2931-2933, (2002).
Preparation, Transport Properties and Structure Analysis by Resonant X-ray Scattering of the Type-I Clathrate Cs8Cd4Sn42, A. P. Wilkinson, C. Lind, R. A. Young, S. D. Shastri, P. L. Lee and G. S. Nolas, Chem. Mater., 14, 1300-1305 (2002).
Kinetics of the Cubic to Trigonal Transformation in ZrMo2O8 and their Dependence on Precursor Chemistry, Cora Lind, Angus P. Wilkinson, Claudia J. Rawn, E. Andrew Payzant, J. Mater. Chem., 12, 990-994 (2002).
Preparation of the negative thermal expansion material cubic ZrMo2O8, Cora Lind, Angus P. Wilkinson, Claudia J. Rawn, E. Andrew Payzant, J. Mater. Chem., 11, 3354-3359. (2001)
New high-pressure form of the negative thermal expansion materials zirconium molybdate and hafnium molybdate, C. Lind, D.G. VanDerveer, A. P. Wilkinson, J. Chen, M. T. Vaughan and D. J. Weidner, Chem. Mater. 13, 487-490 (2001).
A new polymorph of ZrW2O8 prepared using nonhydrolytic sol-gel chemistry, C. Lind, S. Pattanaik and A. P. Wilkinson, Chem. Mater., 11, 101-108, (1999).
Synthesis and properties of the negative thermal expansion material cubic ZrMo2O8, C. L. Lind, A. P. Wilkinson, Z. Hu, S. Short and J. D. Jorgensen, Chem. Mater. 10, 2335-2337, (1998).