While our group lives within the MME department and is primarily affiliated with the metallurgical and materials engineering undergraduate program, graduate research does not fit as easily into traditional bins. We are primarily affiliated with the interdisciplinary Materials Science program in addition to Advanced Energy Systems, Advanced Manufacturing, and Quantum Engineering.
About the Group
We are the Functional Ceramics Group in the Department of Metallurgical and Materials Engineering at the Colorado School of Mines, led by Prof. Geoff Brennecka. We work on the fabrication, characterization, and analysis of functional ceramics, primarily advanced dielectrics, ferroelectrics, and piezoelectrics. Check out our Capabilities page for more details, but in general, we make samples via sputtering, chemical solution deposition, and/or any number of powder-based ceramic processing approaches including 3d printing. We use a suite of chemical and structural characterization techniques as well as a variety of electrical measurement and analysis tools, both commercial and home-built, to understand fundamental structure-processing-property relationships.
What are Functional Ceramics?
We define functional ceramics as the types of advanced dielectrics, ferroelectrics, piezoelectrics, and related materials whose combined (and often coupled) properties allow them to perform functions that other materials simple cannot. Our research focuses primarily on oxides and nitrides that do something fun in the presence of an electric field, but we are interested in just about anything that has to do with the integration, processing, use, or characterization of ceramics (inorganic, non-metallic solids).
At their most basic, dielectrics are simply insulators, but there are many additional functions that come along with sustaining an electric field, ranging from storing charge, energy, and/or information to pulse shaping, filtering, converting, amplifying, rectifying, and just about any other modification you can think of to an electrical or optical signal.
Piezoelectrics are materials that lack a center of symmetry in their crystallographic unit cells such that when a stress is applied to the crystal, the ions displace in a way that leads to a net separation of positive and negative charge centers. This means that not only can the material convert mechanical energy to electrical energy (e.g., stress –> charge), it can also do the converse (e.g., electric field –> strain). An excellent resource for learning more about piezoelectrics is LearnPiezo.
Ferroelectrics are a subset of piezoelectrics (in other words, all ferroelectrics are piezoelectric, but not all piezoelectrics are ferroelectric) that possess a spontaneous polarization at the unit cell level which can be reoriented by application of an electric field. This further increases the various FUNctions that these materials can perform. One of our primary research thrusts is to better understand the dynamic response(s) of ferroelectric materials during this polzarization reorientation (aka switching) process.
Discover, Develop, Deploy
The hundreds of thousands of known inorganic compounds may seem like a lot, but it represents a tiny fraction of the possible combinations of elements from the periodic table. At the same time, simply identifying a new compound makes little impact if it cannot be used for anything. Our group therefore works to discover, develop, and deploy new materials.
We use computational tools such as density functional theory (DFT) and machine learning (ML), both within the group and via collaboration, to help guide our experimental searches, and we collaborate closely with the Materials Discovery Group at NREL to carry out combinatorial fabrication and measurement for high-throughput screening. Once interesting regions in the chemistry – processing space are identified, we zoom in on them to develop a better mechanistic insight and better materials. This includes understanding defect chemistry, microstructure development, and the whole structure-processing-properties package. In order to take advantage of the enabling properties, functional ceramics must be integrated with other materials and processes to perform the desired function(s) under desired (and often challenging) operating environments without costing an arm and a leg. In addition to working through relevant integration challenges, we work with a variety of industry partners to deploy new and improved materials to address real market needs.
Kevin Talley graduates with his PhD!
Congratulations to Kevin Talley for successfully defending this PhD thesis entitled “Understanding Piezoelectric Nitrides by Combinatorial Methods”! Kevin is now a post-doc at NREL.
Chloe Cook graduates with her MS!
Congratulations to Chloe Cook for successfully defending her MS thesis entitled “Development of Chemical Solution Deposited Lead Zirconate Titanate Ferroelectric Thin Films for Non-Planar Substrates”! Chloe is now working at Intel in Hillsboro, OR.
Congratulations to Chloe Cook for running the 7th fastest cross-country time at NCAA Division II nationals and qualifying to be an All-American!
Danny Drury and Nick Rollman join the group!
Welcome to Danny Drury and Nick Rollman! Danny joins us after getting a BS in Ceramic Engineering at Missouri S&T. Nick got his BS in Metallurgical and Materials Engineering at Mines
Katie Gann graduates!
Congratulations to Katie Gann who successfully defended her MS Thesis entitled “Phase Stability, Sintering, and Electrical Properties of the (Mg,Ni,Co,Cu,Zn)O Entropy-Stabilized Oxide System”! Katie is now pursuing her PhD at Cornell.
A review of high-throughput approaches to search for piezoelectric nitrides
K. Talley, R. Sherbondy, A. Zakutayev, and G.L. Brennecka,
J. Vac. Sci. Tech. A. (2019)
In situ TEM study of the amorphous-to-crystalline transition during dielectric breakdown in TiO2 film
X. Tian, C. Cook, W. Hong, T. Ma, G.L. Brennecka, and X. Tan,
ACS Appl. Mater. Interf. (2019)
COMBIgor: data analysis package for combinatorial materials science
K.R. Talley, S.R. Bauers, C.L. Melamed, M.C. Papac, K.N. Heinselman, I. Khan, D.M. Roberts, V. Jacobson, A. Mis, G.L. Brennecka, J.D. Perkins, and A. Zakutayev,
ACS Combinatorial Sci. (2019)
Improving the multicaloric properties of Pb(Fe0.5Nb0.5)O3 by controlling the sintering conditions and doping with manganese
U. Prah, T. Rojac, M. Wencka, M. Dragomir, A. Bradesko, A. Bencan, R. Sherbondy, G. Brennecka, Z. Kutnjak, B. Malic, and H. Ursic
J. Euro. Ceram. Soc. (2019)
In situ TEM study of the amorphization and recrystallization of single crystalline Si under bipolar voltage bias
X. Tian, T. Ma, L. Zhou, G. Brennecka, and X. Tan,
J. Appl. Phys. (2019)
Synthesis of lanthanum tungsten oxynitride perovskite thin films
K. Talley, J. Mangum, C. Perkins, R. Woods-Robinson, A. Mehta, B. Gorman, G.L. Brennecka, and A. Zakutayev
Adv. Electron. Mater. (2019)