Study of nonlinear microwave properties of high-temperature superconducting film

In this thesis, we have explored some of the possible origins of nonlinear properties of high-temperature superconducting films at microwave frequencies. The effect of patterning on the nonlinear microwave surface resistance of HTS films was studied by comparing the results of a dielectric-resonator technique and a stripline-resonator technique. We have concluded that patterning process contributes to neither the low-power surface resistance nor the power dependence of the surface resistance. To understand the grain-boundary contributions to the nonlinear microwave properties, we introduced a coupled-grain RSJ series-array model which simulates an HTS film as a network of ideal superconducting grains, coupled by resistively shunted Josephson junctoins with a distribution of I and Rn parameters. The agreement between the measured and modeled microwave surface resistance suggests the validity of this model. The discrepancy in the microwave surface reactance implies possible long Josephson junction effects. We have investigated the nonlinear microwave properties of engineered HTS grain boundaries systematically, in order to further understand the contributions of grain boundaries. The microwave impedance, second- and third-harmonic generation, and the third-order intermodulation distortion of engineeried bicrystal grain boundaries with misorientation angles of [theta] = 2⁰, 5⁰, 7.5⁰, 10⁰, and 24⁰ were measured using a suspended microstrip resonator with temperature ranging from 5 to 75 K.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Xin, Hao, 1973-

Advisor dc:contributor.advisor

• Daniel E. Oates and Mildred S. Dresselhaus.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8277

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8277