1. National Science Foundation Modeling Real Ceramics Rick Ubic, Boise State University, DMR 1052788 Outcome: Researchers at Boise State University and the University of Illinois at Urbana Champaign have created simple mathematical models for the effective size of defects and their effect on crystal structure in an important class of material used in electronics. Impact: Microwave resonators, superconducting filters, and ionic conductors commonly adopt the perovskite structure and are extensively used in multi- billion-dollar industries. Improving the predictability of their structure and thereby properties could aid size reduction, speed, and quality of a variety of devices. Prof. Ubic and student Steve Letourneau analyzing perovskites on a high-resolution transmission electron microscope (TEM) Explanation: Understanding the way defects, which are common in most engineering ceramics, affect structure and thereby properties is important to both science and industry, yet existing theoretical models are inadequate to describe such ceramics. Our experimental approach involves the use of well-chosen representative systems. Ceramics of precisely controlled chemistries are being synthesized and characterized by advanced techniques. The results are used to derive predictive models for the structure and properties of realistic defect-containing perovskites. Computer modeling may allow for an understanding of the underlying physics of these effects.

2. National Science Foundation Atoms Feel the Pull Rick Ubic, Boise State University, DMR 1052788 Several models have been proposed to predict the structure/stability of perovskite phases; however, none are suited to realistic, complex or defective structures. This project is an attempt to develop such a model. In the case of SrTiO 3 -based compounds, low A-site vacancy concentrations (≤2%) result in vacancies with a negative effective size as a result of geometrical relaxation of anions towards the vacant site. Vacancies essentially pull anions into them. r V(Ca) = (0.93982 + 1.8708[V] + 0.04525/[V])r A(ideal) R 2 = 0.99956 r V(Sr) = (0.88056 + 2.5244[V] – 0.013274/[V])r A(ideal) R 2 = 0.99933 The effective size (normalized) of A-site vacancies Ca 1-3x (La,Nd,Y) 2x TiO 3 Sr 1-3x (La,Ce,Nd) 2x TiO 3 Pnma R3c C2/c For higher concentrations and in CaTiO 3 analogues, vacancies have an effective positive size due to mutual Coulombic repulsion of the coordinating anions. In this case, vacancies push anions away. The relevant equations are:

3. National Science Foundation Telecommunications - Getting the Word Out Rick Ubic, Boise State University, DMR 1052788 Dr. Ubic (PI), Steven Letourneau (graduate student) and Kevin Tolman (undergraduate) presented results from the project as oral presentations in the Microwave Materials and their Applications symposium at the 10 th International Meeting of Pacific Rim Ceramic Societies (PacRim10) held in San Diego, California, 2 – 7 June 2013. This symposium provided a forum for the team to interact with the greater microwave community to discuss not just defect modeling but also materials development, design, measurement techniques, applications, technology trends, and market demands. The conference provided an ideal opportunity to share and discuss ideas and meet with colleagues from a wide variety of backgrounds.