Customer Success Story
LatticeAx™ in Action:
A Unique Three Dimensional Crystalline Material
Learn how scientists at the University of Cambridge used
the LatticeAx cleaving machine to support research into a
three-dimensional material with very unique properties.
It was a discovery that Dr. Suchitra Sebastian of the University’s
Cavendish Laboratory and her team of PhD students weren’t expecting. Their experiments that measured the electronic properties
of samarium hexaboride (SmB6) revealed both insulating and conducting behaviours in the same material, depending on the physical
property measured. This groundbreaking research, published in
Science Magazine in July, 2015, is now challenging accepted principles of material behavior and poses some very interesting questions
for how this material might be used.
To conduct this research, small samples of SmB6 measuring
1 mm2 x 300 µm and oriented along specific directions needed to
be prepared from a larger ingot of 4 mm long and 2.5 mm in diameter, without introducing damage to the material. Alternatives to previously used techniques, including manual cleaving and electro-polishing, were sought to accomplish the required size and orientation.
The hardness of the three-dimensional material, along with its
irregular shape meant that the sectioning could not be performed
with hand tools alone, while electro-polishing presented a risk that
material properties would be altered, or the target facet would be
missed through over-polishing. Neither of these techniques offered
the assurance that they could repeatedly produce the damage-free
samples of the required dimensions and orientation.
Yu-Te Hsu, a PhD student in the Quantum Matter Group, was looking for a way to increase the success rate to at least 50% yield for the
desired sample parameters. This was especially important because
the SmB6 crystals were being grown at the University of Warwick
(Sci. Rep. 3:3071) specifically for the study. Hsu had heard about
the LatticeAx™ from his PhD supervisor, Dr. Suchitra Sebastian, and
they thought it just might be the solution to this challenge of more
consistently achieving damage-free samples of the required dimensions and precise orientation.
The LatticeAx allowed us to
prepare samples meeting our
experiment’s specifications,
with repeatable accuracy
that simply isn’t possible with
hand-held manual cleaving
tools. – Yu-Te Hsu, PhD Student,
Figure 1. Crystal shown following cleaving with the
LatticeAx. The SmB6 cleaved crystal is now ready for experiments to measure electronic properties.
The LatticeAx delivers a method for controlled cleaving of crystalline materials, utilizing a technique called microline indentation. Users are able to control both the location and depth for the
indent using the fine positioning mechanism. The LatticeAx can
be learned in minutes, mastered in hours, and offers a high degree
of flexibility for sample size and dimension. Cavendish Laboratory
connected their own high magnification optical microscope to the
LatticeAx in order to further enable assured placement accuracy for
the initial indent (Figure 4).
To initiate the downsizing process for the ingot, Hsu would first
cut a disc of ~1 mm thickness using a very fine wire-saw. Then
he cleaved that disc using the LatticeAx, making parallel cleaves
perpendicular to the disc plane to arrive at the desired dimension
of 1 mm x 1 mm x 300 µm. The sample was now ready for electrical,
magnetic, and surface characterization. And the crystals with the
highest quality were selected for measurements at the National
High Magnetic Field Laboratory in the United States, under incredibly intense magnetic fields (up to 100 T) and extremely low temperatures (down to 0.03 K).
Figure 2. The SmB6 sample is approximately 4 mm in width
and 1 mm in height, with both cleaved [001] planes. It is
sliced from the ingot; the curved side is the perimeter of
the ingot. Using the optical microscope and computer
display, it is possible to confirm the shape and dimension
for the slice of the material.
he had a good idea about the steps required to get the samples to
the correct size as well as being cleaved along the correct crystal
facet. It took only a single afternoon to figure out the best way to
use the LatticeAx for this three dimensional material.
One interesting aspect to this story has to do with the portability
of the LatticeAx itself. There were times when Hsu would visit a
collaborator’s laboratory, and the compact size of the LatticeAx
allowed him to carry it in his backpack when he travelled. With
collaborators located in both England and the United States, this
portability made it possible for the research to continue when new
material samples were available.
In the end, the LatticeAx allowed Hsu achieve his goal of 50% yield
for samples. He was able to complete the sample preparation required for the research faster, and with a higher degree of accuracy
and repeatability, than he would have been able to accomplish
with hand-tool based manual cleaving tools. And he avoided the
The LatticeAx was able to reliably and repeatedly produce the
required high quality and precisely oriented small samples, even on
this three dimensional material. Hsu attributes this success to two
factors. To start, the SmB6 material has very high crystallinity which
helps facilitate well-defined cleaved surfaces. But without the fine
placement control delivered by the LatticeAx, it would not have
been possible to indent and cleave at the desired site.
It was crucial for Hsu to resolve the [001] direction on the sample
since different crystallographic planes might exhibit different behaviors for this unusual material. Researchers needed to be confident of the sample’s crystallographic direction with respect to the
magnetic field they were applying. For this reason, it was ability to
deliver the precisely oriented crystal facets reproducibly that made
the LatticeAx an important component in this research.
Hsu found that the LatticeAx was extremely easy to use. Because he
had experience using electro-polishing as well as manual cleaving,
Figure 4. Cavendish Laboratory pairs the LatticeAx
base platform with a
Cavendish-supplied optical
microscope and computer.
to further enable assured
placement accuracy for the
initial indent. This cleaving
workstation takes a small
area on a work surface and
is highly portable.
Figure 3. The SmB6 crystal before the final cleave (top) and
after (bottom), with damage free surface at the precise
orientation required for the experiments.
introduction of artifacts or the possibility of overshooting the
target facet that could have occurred with electro-polishing. Most
importantly, Hsu was able to shape the crystal as he downsized,
find the orientation and create a damage-free crystal facet at the
same time using the LatticeAx, tasks which would have taken at
least one week of work using conventional methods.
Hsu and his colleagues are currently working on further studies on
SmB6 and other closely related materials, hoping to see more exotic behaviors, and LatticeAx will keep working as their “Excalibur”.
Go online to learn more about Cavendish
Laboratory’s ground breaking research:
University of Cambridge Research News
To conduct, or to insulate? That is the question
Click here to read, or search from:
http://www.cam.ac.uk/research/news
Quanta Magazine Online:
Paradoxical Crystal Baffles Physicists
Click here to read online or search from
https://www.quantamagazine.org
Science Magazine:
Unconventional Fermi surface in an insulating
state
Click here to view the abstract or search from
http://www.sciencemag.org
Vol. 349 no. 6245 pp. 287-290; DOI: 10.1126/science.aaa7974
About LatticeGear, LLC.
Company founders Janet and Efrat, two women
with extensive applications experience in the
semiconductor industry, believe that scribing and
cleaving can be accurate, repeatable, easy and fast.
They started LatticeGear in 2012 to provide
solutions and resources that help technicians,
engineers and researchers increase throughput
and productivity for their sample preparation
workflows.
From kits that take the guesswork out of selecting
supplies for a specific use case, to compact desktop
scribing and cleaving machines designed for speed,
ease of use and high quality results, LatticeGear
solutions are helping to alleviate sample preparation challenges in materials research and failure
analysis labs around the world.
LatticeAx is a trademark of LatticeGear.
LatticeGear LLC • 15201 NW Greenbrier Parkway • Suite C-7
Beaverton, OR 97006 • +1-503-828-0040 • US Toll Free: 1-800-430-8210
[email protected] • latticegear.com
January 31, 2016