Subcategory: Physics (not Nanoscience)
Kevin Jimenez - Farmingdale State College
Co-Author(s): J. Brown and J. W. Simonson, Farmingdale State College, Farmingdale, NY
Single crystals of high quality are essential to measuring the intrinsic properties of novel materials, such as transport and magnetic properties. Nevertheless, in many cases growth of the preferred crystals may be deterred by the appearance of competing phases, resulting in a scarcity of the preferred phase of the crystal or even a reduction in the size of the crystals themselves. We present here an innovative method and show that it is possible to subdue the formation of competing crystalline phases and to achieve high quality crystals of the desired phase by exposing said growths to high frequency electromagnetic radiation from frequencies of 0.24 MHz to 18 GHz. In the Cr-Ge-C system, for instance, we can alternatively suppress or promote the growth of Cr2GeC  and Cr3GeC  crystals depending on frequency. At optimal frequency of 240 MHz, the size of Cr3GeC crystals was increased from 500 μm to 1600 μm, a more than 200% improvement, while the size of Cr2GeC crystals is similarly enhanced at frequencies above 2.4 GHz. We propose further research into the effects of higher intensity RF fields as well as the application of this process to other materials systems, including those related to the high temperature pnictide superconductors.
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Funder Acknowledgement(s): Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research under contract 56764-UNI10. K. V. Jimenez was supported by an NYSED CSTEP Grant, under Contract No. C401633 and by the NSF under the LSAMP program.
Faculty Advisor: J. W. Simonson, firstname.lastname@example.org
Role: Design and construction of instrumentation, synthesis of samples, operation of RF generators, analysis of results.