Marleen Kamperman
(Contact: E. Fontes - ef11@cornell.edu)
Two Cornell graduate students had their posters
chosen for prizes at the 2007 Fall Meeting of the Materials Research
Society (MRS) held November 26 – 30 in
John
Ferguson, a graduate student with advisor Joel Brock in
the Applied and Engineering Physics (A&EP) department, presented a
poster entitled “Time Resolved In-Situ Diffuse X-ray Scattering
Measurements of the Surface Morphology of Homoepitaxial SrTiO3
Films during Pulsed Laser Deposition.”
Collaborators from the
Ferguson’s poster highlighted very recent results of an ongoing project to study thin film growth in strontium titanate. Strontium titanate is one of a large class of complex oxide materials that exhibit a wide variety of unexpected physical, electronic and magnetic properties. Surprising, for example, is that two electrically insulating materials such as these can combine to produce a buried interface that is electrically conductive. As promising as these materials are for technological applications, though, detailed experimental information about their growth is still very limited and obtaining such information is an ongoing challenge.
Poster prizewinners John Ferguson
(second from right)
and Arthur Woll (second from
left) with judges.
The Pulsed Laser Deposition (PLD) growth system
built into the G3 experimental station at CHESS was
designed to address these challenging systems.
There, the growth of homoepitaxial thin films can be
monitored during the deposition process via both
x-ray reflectivity and surface diffuse x-ray
scattering measurements.
Perfecting the diffuse scattering
measurements was an innovation
Figure 2: X-ray scattering geometry using the CCD
area detector in a “streak camera mode” (a) and
measured diffuse scattering profiles from the small
islands on the otherwise flat surface (b). The
central peak is a Bragg reflection and the side
lobes due to diffuse scattering.
Black points
are experimental values and the colored lines are
lineshape fitting results.
[1]
The most compelling (and remarked
upon) aspect of
Figure 3: AFM
image of the as-grown strontium titanate thin film
showing small island formation on terraces.
The insert shows a larger area scan.
[1]
Cornell won two out of three poster prizes Thursday night when graduate student Marleen Kamperman was also awarded a prize for her poster entitled “Porous High Temperature Ceramics Structured on Multiple Length Scales.” Kamperman is a graduate student with Ulrich Wiesner in the department of Materials Science and Engineering and shared the prize with coauthors Robert Weissgraeber and Andrew Burns. She reported on how they fabricated porous high temperature ceramics with hierarchically ordered pore structures and discussed how these structures offer great promise in structural applications because of their excellent thermal stability and mechanical properties in combination with a high surface area and low flow resistance. They developed an easy to control bottoms-up approach towards hierarchically ordered high temperature ceramics structured on multiple length scales, from a few nanometers to tens of microns. They structured the ceramics by combining micromolding, latex sphere templating and cooperative assembly of a polysilazane with an amphiphilic block copolymer. Relatively large micron-sized latex spheres were found to self-assemble into an ordered lattice in the channels of a micromold. Smaller latex nanospheres packed closely in the interstices between the micron-sized spheres. During both the poster session and later at an oral presentation Kamperman discussed implications of these findings for various applications of these model ceramic systems.
Figure 4:
Poster prizewinner Marleen Kamperman (center) with
judges.
The day before gaining additional notoriety for her poster, Kamperman was one of six graduate students chosen to be honored with a “Graduate Student Gold Award.” On Wednesday evening MRS Society First President Alan Hurd presented awards to graduate students who authored or co-authored symposium papers that exemplified significant and timely research. She earned this honor for her paper on porous high temperature ceramics presented during the special session on Tuesday afternoon.
Kamperman came to Cornell via
In retrospect Marleen says of the MRS meeting: “Winning the awards was one thing, but the nice mail from people who found out [about our work] and congratulations are the most rewarding.”
CHESS is proud of the excellent work the graduate
students were able to accomplish and congratulates them on their
outstanding posters and prizes.
[1] Figures 2 and 3 from: John David Ferguson, Gokhan Arikan, Arthur R. Woll, Darren S. Dale, Aram Amassian and Joel Brock; Time Resolved In-Situ Diffuse X-ray Scattering Measurements of the Surface Morphology of Homoepitaxial SrTi03 Films During Pulsed Laser Deposition, in Ferroelectrics, Multiferroics, and Magnetoelectrics, edited by J.F. Scott, V. Gopalan, M. Okuyama, and M. Bibes (Mater. Res. Soc. Symp. Proc. Volume 1034E, Warrendale, PA, 2007).
