B.S. Physics, Colorado State University, 1983Ph.D. Materials Science and Engineering, MIT, 1992Post-Doc at Sandia National Laboratories, New Mexico, 1992-1994
"Making better materials --> every atom in its place."
Jerry Floro, Professor
My passion in research is to investigate and exploit nanoscale self-assembly and pattern formation in inorganic materials, to enhance properties and develop material functionality. My group employs a range of techniques to synthesize materials, including vapor phase thin film growth, laser processing, melting and rapid solidification (including additive manufacturing), powder processing, and solid-state phase transformations. There is plenty of room at the bottom -- and there is both beauty and mystery there as well.
Bio: I earned my Bachelor's degree in Physics at Colorado State University in 1983, where I did research on modification of surfaces using low energy ion beams, including a project that was likely producing carbon nanotubes before they were "a thing". I then joined the IBM Thomas J. Watson Research Center in Yorktown Heights, NY, where I learned multiple thin film deposition techniques, materials characterization, vacuum technology, and got a great exposure to different sorts of research going on at a very vibrant place. I first heard about Materials Science as a field of study here, and then joined MIT's Ph.D. program in MSE in 1986. My thesis research investigated grain growth in thin films driven by anisotropic surface energy and elastic energy. After finishing in 1992, I began a post doc at Sandia National Labs in Albuquerque, NM. Over the next 14 years, I worked on epitaxial and thin film growth sicence, including quantum dot self-assembly in Group IV semiconductors, the origins of residual stresses in thin films, and strain relaxation mechanisms in III-nitride layers and heterostructures. During this time I helped co-invent the multi-beam optical stress sensor and the light-scattering spectrometer, for real-time, in situ investigation of evolving stress and surface morphology during film growth. In 2006, feeling that my strengths were best suited to academia, I joined the faculty of UVa in the Materials Science and Engineering department. My research currently has migrates towards bulk materials processing via rapid solidfication, thermomechanical treatment, powder processing, and/or solid-state phase transformations. I still maintain and use capabilities in thin film growth and processing. These varied approaches are especially useful for new nanoelectronic, thermoelectric and ferromagnetic materials.
Hartfield-Jefferson Scholars Teaching Prize2012
DOE Materials Science Award for Sustained Outstanding Research in Metallurgy and Ceramics1994
Pattern formation across lengthscales by self-assembly
Microstructure control in additive manufacturing
Thermoelectric materials and thermal transport
Residual stress in thin films
Nanomaterials and nanomanufacturing
Efficacy of elemental mixing of in situ alloyed Al-33wt%Cu during laser powder bed fusion ABSJ.M. Skelton, E.J. Sullivan, J.M. Fitz-Gerald and J.A. Floro
Lamellar instabilities during scanning laser melting of Al-Cu eutectic and hypoeutectic thin films ABSE.J. Sullivan, J.A. Tomko, J.M. Skelton, J.M. Fitz-Gerald, P.E. Hopkins, and J.A. Floro
Improved Thermolectric Performance of Eco-Friendly b-FeSi2-SiGe Nanocomposite via Synergistic Hierarchical Structuring, Phase Percolation and Selective Doping, Adv. Funct. Mater. 1903157 (2019). ABSNaiming Liu, S. Emad Rezai, Wade Aaron Jensen, Shaowei Song, Zhifeng Ren, Keivan Esfarjani, Mona Zebarjadi and Jerrold Anthony Floro
On the morphology changes of Al and Al-Cu powder after laser melting ABSJ. Skelton, C. V. Headley, E. J. Sullivan, J. M. Fitz-Gerald and J. A. Floro
Synthesis and thermal transport of eco-friendly Fe-Si-Ge alloys with eutectic/eutectoid microstructure; Mat. Chem. Phys. 207, 67-75 (2018). ABSWade A. Jensen, Naiming Liu, Brian F. Donovan, John A. Tomko, Patrick E. Hopkins, and Jerrold A. Floro
Hierarchical structure and the origins of coercivity in exchange-coupled Co-Pt nanochessboards ABSJ.A. Floro, E.P. Vetter, P. Ghatwai, L.D. Geng, Y.M. Jin, W.A. Soffa
Lengthscale effects on exchange coupling in Co-Pt L10 + L12 nanochessboards; APL Mater. 4, 096103 (2016). ABSEric P. Vetter, Liwei Geng, Priya Ghatwai, Dustin A. Gilbert, Yongmei Jin, William A. Soffa and Jerrold A. Floro
Evolution of microstructure and magnetic properties in Co–Pt alloys bracketing the eutectoid composition; J. Magn. Magn. Mater. 375, 87-95 (2015). ABSP. Ghatwai, E. Vetter, M. Hrdy, W. A. Soffa and J. A. Floro
L1′ ordering: Evidence of L10–L12 hybridization in strained Fe38.5Pd61.5 epitaxial films; Acta Mater. 85, 261-269 (2015). ABSMatthew A. Steiner, Ryan B. Comes, Jerrold A. Floro, William A. Soffa and James M. Fitz-Gerald
Mn solid solutions in self-assembled Ge/Si (001) quantum dot heterostructures, Appl. Phys. Lett. 101, 242407 (2012). ABSJ. Kassim, C. Nolph, M. Jamet, P. Reinke, J. Floro
Epitaxial Si encapsulation of highly misfitting SiC quantum dot arrays formed on Si (001); Appl. Phys. Lett. 104, 013108 (2014). ABSC. W. Petz, D. Yang, A. F. Myers, J. Levy, and J. A. Floro
Misfit dislocation formation in the AlGaN/GaN heterointerface; J. Appl. Phys. 96, 7087-7094 (2004). ABSJ. A. Floro, D. W. Follstaedt, P. Provencio, S. J. Hearne and S. R. Lee
SiGe Island Shape Transitions Induced by Elastic Repulsion; Phys. Rev. Lett. 80, 4717 (1998). ABSJ. A. Floro, G. A. Lucadamo, E. Chason, M. Sinclair, R. D. Twesten and R. Q. Hwang
The Dynamic Competition Between Stress Generation and Relaxation Mechanisms During Coalescence of Volmer-Weber Thin Films, Appl. Phys. 89, 4886 (2001) ABSJ. A. Floro, S. J. Hearne, J. A. Hunter, P. Kotula, E. Chason, S. C. Seel and C. V. Thompson, J.
Introduction to Materials Science and Engineering - Guided Inquiry (MSE 2090)Spring
Formerly: Introduction to the Crystal and Electronic Structure of Materials (MSE 6010)Fall
Featured Grants & Projects
Additive Manufacturing of Thermally Stable Freeform Optical Reflectors Through Engineered Composites
This research develops an additive manufacturing (AM) process for fabricating Invar-copper composite optical mirrors with freeform geometry. The composite consists of a thin copper network embedded in the Invar matrix and is formed naturally from rapid solidification by microsegregation engineering and alloy design. The result combines the near-zero coefficient of thermal expansion of Invar with the high thermal conductivity afforded by the percolating copper network to create an ideal material for high precision optics with minimal thermal distortion. AM overcomes the incompatibility of Invar with conventional diamond turning – used to create complex mirror geometries – due to excessive tool wear and enables optics with arbitrary geometry to be created from this material. We use laser powder bed fusion processing, which uniquely exploits solidification conditions and elemental partitioning. The project investigates the solidification characteristics of the alloy system, determines the optimal composition for achieving such microstructure, and builds the foundational knowledge that will enable manufacturing of high-performance optical devices and materials.
Selection of Lengthscales in Fe-based Nanochessboards to Enhance Exchange-Coupled Ferromagnetism
National Science Foundation, Division of Materials Research
A key strategy for improving the performance of permanent magnets is to create a nanocomposite
structure that includes both magnetically "hard" and "soft" phases. The former has high coercivity, so it
resists switching its polarity, while the latter can have high magnetization. If the phases can be
interleaved on lengthscales of order 10 nm, then exchange-coupling can lead to improved magnetic
energy storage. Exchange-coupled ferromagnetism has been studied in epitaxial thin film systems, which
serve as idealized one-dimensional models, but are not realistic representations for permanent magnets.
Three-dimensional nanocomposite magnets are also heavily studied, but these often have complex
structures and are correspondingly complex to interpret. The unique nanochessboard structure represents
an intermediate case - formed in bulk alloys by a solid-state transformation, chessboards have a highly
regular two-phase microstructure that is well-suited to investigations on the role of lengthscales in
controlling the exchange coupling. The challenge is to select and control the structural lengthscales of the
chessboard in the best range to enhance the coupling.
Collaborative Research: Formation and Stability of Eutectic Nanostructures in Laser-Irradiated Particle Suspensions
National Science Foundation, Division of Civil, Mechanical and Manufacturing Innovation
The overarching goal of this research program is to investigate controlled formation of eutectic microstructure in metallic and ceramic powders, towards improving the properties of sintered materials and to provide a better understanding of microstructure evolution during additive manufacturing. Laser melting is used to melt the powder particles, and both the laser parameters and the ambient boundary conditions can be modified to determine the effect of heat removal and control nucleation. The project will determine how the resultant eutectic microstructure, including its lengthscales, morphology, and heterogeneity, depend on the particle size, and on the local boundary conditions for heat removal, which can be modified by varying the nature of the powder suspension. The project will also examine the subsequent stability of this microstructure with respect to varying thermal budgets relevant to sintering and additive manufacturing.