Ph.D., University of Maryland, College Park, 1996
Applications of combinatorial synthesis and characterization methodology to electronic, magnetic and smart materials; fabrication and characterization of novel multilayer thin-film devices; variable temperature scanning probe microscopes.
Current Research Projects
Combinatorial Investigation of Functional Materials
We have developed a comprehensive methodology for rapid mapping of previously unexplored compositional landscape in search of novel multifunctional materials. A variety of thin film deposition tools are implemented for synthesis of combinatorial thin film libraries and composition spreads of various designs. A suite of rapid characterization tools are utilized for quantitative mapping of relevant physical properties across combinatorial libraries. These include microwave microscopes, a scanning magneto-optical Kerr measurement setup and scanning x-ray diffractometers. Current topics of interest include magnetistrictive materials, multiferroic materials, and shape memory alloys. Our recent emphasis has also been on development of informatics techniques to effectively handle, visualize, and analyze the large amount of data which are generated from the combinatorial experiments. We have a network of international collaborators with whom a number of combinatorial experiments are carried out at any given time.
- See also:
Novel Multilayer Thin Film Devices
Previously I had worked on fabrication and characterization of superconducting thin film devices for over 10 years. My interest in novel functional devices now spans a range of other materials including magnetic materials and various smart materials. Our current projects include various multilayer multiferroic devices.
Scanning Probe Microscopy
Many of the rapid characterization tools used for screening combinatorial libraries are scanning probe microscopes. For instance, we work extensively with scanning SQUID microscopes (in collaboration with Neocera, Inc.) and scanning microwave microscopes. We have recently demonstrated high sensitivity scanning magnetic probe microscopy using a magnetoelectric device. Our current project includes development of novel microwave microscopy combined with atomic resolution STM for performing spin resonance measurements.
Current and Recent Group Members Include:
- A. Gilad Kusne (NIST)
- Xiaohang Zhang
- Tieren Gao
- Seunghun Lee
- Ippei Suzuki
- Huilong Hou
- Yangang Liang
- Naila Al Hasan
- Eric Marksz
- Jaim H.M. Iftekhar
- David Catalini (ME)
- Aditya Shanbhag (Computer Science)
- Matt Reilly
- Drew Stasak
- Edward Morozov
Honors and Awards
Elected APS Fellow (2011)
Invention of the Year Award, Physical Sciences Category, University of Maryland (2011)
- Visiting Associate Professor, Institute for Solid State Physics, University of Tokyo, Kashiwa, Japan (4/2007—8/2007)
- Fellow by Special Appointment, Japan Science and Technology Agency (2007)
- Visiting Associate Professor, Applied Ceramics Laboratory, Tokyo Institute of Technology, Yokohama, Japan (6/2004—3/2005)
- NSF CAREER Award (2001)
- Office of Naval Research, Young Investigator Program Award (2000)
- Oak Ridge Associated Universities Ralph E. Powe Junior Faculty Enhancement Award (2000)
- General Research Board Semester Research Award, University of Maryland (2000)
- Associated Western Universities Postdoctoral Research Fellowship (1996-1999)
- National Center for Electron Microscopy Visiting Scientist Fellowship, Lawrence Berkeley National Laboratory (1999)
- Summer Undergraduate Research Fellowship, Caltech (1985 & 1986)
- American Physical Society
- Materials Research Society
For a closer look at my research, take a look at the video links below:
Combinatorial Time Lapse - A video made by Sean Fackler showing how a composition spread wafer of permanent magnet materials is made; X-ray diffraction and MOKE measurements are carried out at every spot.
Dwight Quench: We have developed a technique where an entire thin film on a wafer can be quenched from a high temperature. In the movie, a thin-film composition spread wafer mounted inside a narrow high-vacuum chamber pumped by a cryopump is annealed in a furnace at 800 C. For quenching the wafer, it is “quickly” pulled out of the furnace, and the chamber is dunked in an ice bucket. This results in formation of quenched thin film phases as reported in Ref. 102, Applied Surface Science 254, 725 (2007) and Ref. 147, Nature Communications 2, 518.
FeCoNi XRD contourslices-2: Visualization of X-ray diffraction patterns from the entire Fe-Co-Ni composition spread. The big triangular shaped blob corresponds to the main fcc peak showing significant shift as a function of composition. The thin oval blob near the Fe end is the bcc main peak. Shown on the cover of Ref. 95.
IchiroCombi with Targets: Combinatorial pulsed laser deposition of epitaxial oxide thin films. The movie shows the synthesis process of an epitaxial composition spread onto a heated substrate. Two targets (with end compositions) are used to deposit alternating ultrathin gradient thickness wedges using a synchronized moving shutter gliding over the substrate. The thickness of the wedge is designed to be less than a unitcell. The deposition of hundreds of wedges results in mixing of the end compositions at the unitcell level during the deposition at an elevated temperature. The composition continuously varies on the substrate from one end composition to the other. Each composition spread sample is roughly 7-10 mm long. This technique is used for continuous substitution experiments. See for instance, Ref. 71,72, 85, 100.
XRDSuite: demo of early combinatorial X-ray diffraction data visualization and analysis tool. One can see a large number of diffraction patterns in a number of different ways. Ref. 76. Review of Scientific Instruments 76, 062223 (2005).
NiMnAl – Sepctrum Scroller: Another demo of XRDSuite. Ref. 76. Review of Scientific Instruments 76, 062223 (2005).
NiMnAl – Peak Plotter (Full Spectrum with Mag): Comparison of diffraction patterns of Ni-Mn-Al composition spread and magnetism. With one look, one can see which diffraction peaks (and phases) are responsible for the composition regions with strong remnant magnetization (measured by scanning SQUID). Ref. 76. Review of Scientific Instruments 76, 062223 (2005).
Demo of CombiView: software to carry out rapid visualization and cluster analysis of a large number of diffraction patterns taken from combinatorial libraries. Video courtesy of R. Zarnetta and A. Ludwig. Ref. 125. Review of Scientific Instruments 80, 103902 (2009).
Demonstration of 1 kW tension-based thermoelastic cooler: One can see the rotating birdcage design in operation. Thermoelastic wires are connected to two rings (one at top and another at bottom). Because the rings are set not to be on parallel planes, wires stretch and unstretch as they rotate. See Ref. 190.
Infrared camera video of 1 kW tension-based thermoelastic cooler. In the foreground are thermoelastic wires are being stretched as they rotate to the right, and they are releasing heat. In the background are the wires now being uploaded and are thus cold rotating back to left. See Ref. 190.