Hope College Physics Department
Research Experiences for Undergraduates
|Project Title:||Characterization of High Temperature Superconducting Microstrip Lines|
|Student Name:||Annelle Eben|
|Student's Home Institution:||Calvin College|
|Research Advisor:||Dr. Stephen Remillard|
|Source of Support:||
This material is based upon work supported by the National Science Foundation under NSF-REU Grant No. PHY/DMR-1004811 as well as by a Cottrell College Science award from the Research Corporation for Science Advancement.
When two or more frequencies are sent through a High Temperature Superconducting
(HTS) resonator, intermodulation (IMD) and harmonic distortion is generated.
Because distortion is dependant on the physical properties of the HTS microstrip
lines, the microstrip lines were analyzed optically with a traveling microscope
to determine their dimensions. Using these dimensions, electromagnetic field
simulations with IE3D from Zeland Software provided information about current
distributions and the geometry factors of the microstrip lines. The edges of
the microstrip lines were imaged with an electron scanning microscope because
their microstructure corresponds to fluxon nucleation, which increases the
distortion. Multi-tone measurements can be performed to detect the distortion,
of which the three-tone method developed at Hope College allows for simultaneous
and synchronous measurement of even and odd order distortion currents. Contrary
to earlier predictions of solely odd order distortion arising from HTS materials,
both even and odd order non-linearity was observed, indicating Time-Reversal
Symmetry Breaking (TRSB) in superconducting current. The second and third order
distortion measurements are pertinent to current research in HTS in multiple
ways: the distortion defines the limitations of microwave technologies and
it reveals the fundamental physics of HTS materials. An observed catastrophic
increase in the odd order IMD near the phase transition corresponds to the
anticipation of the non-linear Meissner effect in HTS. A smaller observed catastrophe
in the even order IMD has no current theoretical explanation, but the significant
drop in the ratio of second to third order IMD at the phase transition indicates
a decline in TRSB.
Publications and Presentations:
S.K. Remillard and Anelle M. Eben, Calvin College Department of Physics and Astronomy, "Time Reversal Symmetry Breaking in Superconducting Devices." 2010 department seminar.
"Even and Odd Order Nonlinearity from Superconductive Microstrip Lines,"Annelle M. Eben, V. Andrew Bunnell, Candace J. Goodson, Evan K. Pease, Sheng-Chiang Lee, and S.K. Remillard, IEEE Trans. on Applied Superconductivity, Vol. 21, no. 3, pp. 595-598, (2011).