Browsing by Author "Watanabe, T."

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Experimental Presentation of Microwave Absorption due to Shaking of JV by AC Magnetic Field in Bi2212 and Bi2223
(2009-05-01)
Shaltiel, D.
;
von Nidda, H. -A. Krug
;
Shapiro, B. Y.
;
Rosenstein, B.
;
Loidl, A.
The Josephson Vortex dynamics in high anisotropy superconductors Bi2212 and Bi2223 induced by AC magnetic field collinear to DC magnetic field and parallel to the layers is studied via their interaction with microwave field. Experimental results as function of DC magnetic field, AC magnetic field and temperature are presented. The AC induced microwave dissipation is larger than dissipation without AC field. The results are explained by the theoretical interpretation reported recently due to shaking by the AC field that depins the JV (Shaltiel et al., Phys. Rev. B 77, 014508, 2008). Similar behavior in these two compounds as a function of the variables involved discloses that the shaking effect should be observed in any high anisotropy superconductors. It shows that the AC field interacting with JV has an active and not the usual passive modulating role of the DC field in EPR dissipation experiments. The technique can be used to investigate JV dynamics and JV phase diagram.
Field cooling memory effect in Bi2212 and Bi2223 single crystals
(2010-07-01)
Shaltiel, D.
;
von Nidda, H-A Krug
;
Rosenstein, B.
;
Shapiro, B. Ya
;
Golosovsky, M.
A memory effect in the Josephson vortex system created by a magnetic field in the highly anisotropic superconductors Bi2212 and Bi2223 is demonstrated using microwave power absorption. This surprising effect appears despite a very low viscosity of Josephson vortices compared to Abrikosov vortices. The superconductor is field-cooled in a DC magnetic field H(m) oriented parallel to the CuO planes through the critical temperature T(c) down to 4 K, with subsequent reduction of the field to zero and again above H(m). A large microwave power absorption signal is observed at a magnetic field just above the cooling field, clearly indicating a memory effect. The dependence of the signal on a deviation of the magnetic field from H(m) is the same for a wide range of H(m) from 1500 to 17 000 G.
Interaction of AC magnetic field with Josephson vortices in high anisotropy superconductors Bi2212 and Bi2223
(2007-09-01)
Shaltiel, D.
;
von Nidda, H.-A. Krug
;
Shapiro, B. Ya.
;
Shapiro, I.
;
Loidl, A.
We show that in both high anisotropy superconductors Bi2212 (T-c = 90 K), and Bi2223 (T-c = 110 K), an AC magnetic field applied collinear to the DC field and parallel to the Cu layers induces strong microwave dissipation. It is theoretically predicted that the Josephson solitons are responsible for this absorption. Good qualitative agreement of experimental data with theoretical predictions is found. Differences observed in the experimental results between these two compounds are discussed. (c) 2007 Elsevier B.V. All rights reserved.