Interviews with plenary speakers of the XIV SBPMat Meeting: Ichiro Takeuchi.

The search for the materials that are most suitable for performing certain tasks maybe exists since the dawn of humanity. In this search, on the opposite end to the trial and error method, there is the combinatorial approach, which aims to increase the efficiency of the process of discovering or producing materials. This approach is based on the screening of large amounts of materials with compositions slightly different one another, using databases, rapid synthesis and characterization techniques, simulations, robots and other tools. The combinatorial approach has been applied to the pharmaceutical industry since the 1990s to identify new and useful compounds, and it also has its place in the field of Materials Science and Engineering.

Prof. Ichiro Takeuchi

During the XIV SBPMat Meeting, Professor Ichiro Takeuchi will give a plenary talk on the combinatorial approach to materials discovery – an issue that is part of his daily life. Takeuchi is a Professor of the Materials Science and Engineering Department at the University of Maryland, in the United States, since 1999. In this institution, he leads the Combinatorial Synthesis and Rapid Characterization Center and the Keck Lab for Combinatorial Nanosynthesis/ Multiscale Characterization. He is a Visiting Professor at the Tokyo University of Science since 2010. He is also member of the Executive Committee of the Forum on Industrial & Applied Physics from the American Physical Society (APS). 

Takeuchi graduated with a Degree in Physics in 1987 at the California Institute of Technology (Caltech). For four years he worked in Japan at the microelectronics research laboratories of the NEC Corporation, to later return to the United States. In 1996, he earned his Ph.D. at the University of Maryland. Then, he went to the Lawrence Berkeley National Laboratory, where he stayed until 1999 as a postdoctoral researcher. In 2004, he was the chairman of the Gordon Conference on Combinatorial and High-throughput Materials Science. In 2009, he founded a company dedicated to the development of materials and systems for applications in the field of energy, the Maryland Energy and Sensor Technologies, LLC.

Ichiro Takeuchi was a Visiting Professor at universities in Japan and Germany. He has received awards and distinctions from the National Science Foundation (Career Award), the Office of Naval Research in the US (Young Investigator Program Award) and the University of Maryland, among other institutions. The scientist, whose H index is 40, according to Google Scholar, is the author of over 180 papers, with more than 5,900 citations, and a book on the combinatorial synthesis of materials.

What follows is a brief interview with this plenary speaker.

SBPMat newsletter: – Help us to visualize how the combinatorial research is performed. For instance, choose an example of a material created in your laboratories with this approach, and outline the “step-by-step”.

Synthesis of thin-film combinatorial library: in this example, co-sputtering (a) is used to generate large compositional variation across a 3” wafer (b); such a sample is called a composition spread wafer; the composition variation is mapped on to ternary compositional phase diagram using electron probe (c).

Ichiro Takeuchi: – We do thin film based combinatorial materials research. The goal is to carry out rapid screening of previously unexplored compositional landscape in order to discover new materials with enhanced physical properties. We make wafers or chips where there are large composition variations in deposited thin films. Sometimes the thin films are separated into different pads, and sometimes it is one continuous film with changing composition across the wafer. We want the variation to be as large and diverse as possible, so that we can map large compositional variation in a single experiment. We then take different characterization techniques to carry out rapid screening of various physical properties. For example, right now, we have a project to search for new permanent magnet materials. For this, we use techniques such as scanning SQUID or scanning magneto-optical Kerr effect measurements. These measurements can be used to map magnetic properties of all the compositions on a single wafer. These wafers and chips are called combinatorial libraries. We also do a lot of structural characterization. For this purpose, we often go to synchrotron beamlines. At such locations, because of the large beam flux, we are able to carry out x-ray diffraction of the entire wafer very quickly. Right now, we can scan 200-300 spots in 2 hours.

SBPMat newsletter: – In your opinion, what are your most significant contributions in the field of combinatorial materials science? Please explain them, very briefly, and share references from the resulting articles or books, or comment if these studies have produced patents, products, spin-off companies etc.

Examples of combinatorial libraries of functional materials and visualization of their data: (a) permanent magnet library for systematic investigation of exchange coupling showing magnetic hysteresis loops taken at each spot on the library (from Physical Review B75, 144429 (2007)); (b) ferroelectric library displaying ferroelectric hysteresis loops measured at each spot (from Journal of Materials Research 27, 2691 (2012)); (c) superconductor library with resistance – temperature curves mapped onto the positions where they were measured (from APL Materials 1, 042101 (2013)).

Ichiro Takeuchi: – Over the years, we have carried out combinatorial investigation on a variety of topics in the general field of functional materials. They include superconductors, shape memory alloys, magnetosrictive materials, ferroelectric and dielectric materials to name a few. In carrying out such experiments, we have had to develop and establish techniques to effectively implement the strategies. We have indeed discovered a number of new compounds. For instance, working together with theoretical colleagues, we have found shape memory alloys with long fatigue lives. I have patents on a number of low-loss dielectric materials as well as novel piezoelectric materials. Many groups are now doing follow-on work on a lead-free morphotropic phase boundary piezoelectric material we found a number of years ago. In addition to the materials that were discovered, we have established combinatorial strategies as a technique to rapidly delineate composition-structure-property relationships in different materials systems. We have recently published a comprehensive review article. It is: “Applications of high throughput (combinatorial) methodologies to electronic, magnetic, optical, and energy-related materials,” Journal of Applied Physiscs 113, 231101 (2013) by Martin L. Green, Ichiro Takeuchi, and Jason R. Hattrick-Simpers.

SBPMat newsletter: -If you wish, leave a message or an invitation to your plenary talk to the readers who will attend the XIV SBPMat Meeting.

Ichiro Takeuchi: – The notion of search and discover is central to materials research. The combinatorial methodology is the natural counterpart to the concerted efforts in theoretical design of materials taking place around the world. By effectively coupling theory with high-throughput experimentation, we can really accelerate the rate at which new materials are discovered. I will present a mode of research we call “integrated materials engine” where theory and experiments are woven together and built on a flexible database and data management platform.

Integrated materials discovery engine: we propose coupling of high-throughput combinatorial materials exploration with theoretical investigation. Multiple feedback points between the two tracks ensure that we carry out accelerated exploration effectively.