Observation of individual Josephson vortices in YBa2Cu3O7Àd bicrystal grain-boundary junctions
نویسندگان
چکیده
The response of YBa2Cu3O72d bicrystal grain-boundary junctions to small dc magnetic fields ~0–10 Oe! has been probed with a low-power microwave ~rf! signal of 4.4 GHz in a microwave-resonator setup. Peaks in the microwave loss at certain dc magnetic fields are observed that result from individual Josephson vortices penetrating into the grain-boundary junctions under study. The system is modeled as a long Josephson junction described by the sine-Gordon equation with appropriate boundary conditions. Quantitative agreement between the experimental data and the model has been obtained. The hysteresis effect of dc magnetic field is also studied and the results of measurement and calculation are compared.
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