Observation of Structures of Chain Vortices Inside Anisotropic High-TcSuperconductors

Abstract

In order to elucidate the formation mechanism of unconventional arrangements of vortices in high- Tc superconducting thin films at an inclined magnetic field to the layer plane, we investigated the structures of vortex lines inside the films by Lorentz microscopy using our 1-MV field-emission electron microscope. Our observation results concluded that vortex lines are tilted to form linear chains in YBaCu3O(7,8). Vortex lines in the chain-lattice state in Bi2Sr2CaCu2O(8+delta), on the other hand, are all perpendicular to the layer plane, and therefore only vortices lined up along Josephson vortices form chains.

Direct observation of thitherto unobservable quantum phenomena by using electrons

“…In the case of YBaCu 3 O 7.8 , the conclusion is evident from the obtained Lorentz micrographs (64) in Fig. 11.…”

“…An electron wave was incident on a tiny toroidal sample, and the phase difference ⌬ between 350-kVFEEM(5) 5 ϫ 10 9 Dynamic observation of vortices in metal superconductors (7) 2000 1-MV FEEM(6) 2 ϫ 10 10 Observation of unusual behaviors of vortices in high-Tc superconductors (8,64,65) 11,000 (9) TEEM, thermal-emission electron microscope; FEEM, field-emission electron microscope. …”

Properties of Macroscopic Quantum Effects and Dynamic Natures of Electrons in Superconductors

“…(67)- (68) Recently, Garadoc-Daries et al [68], Matthews et al [69] and Madison et al [70] observed vertex solitons in the Boson-Einstein condensates. Tonomure [71] observed experimentally magnetic vortexes in superconductors. These vortex lines in the type-II-superconductors are quantized.…”

Imaging flux vortices in type II superconductors with a commercial transmission electron microscope

“…In a finite solenoid stray field leaks near the ends, reducing the overall energy since less flux is enclosed by the current. The energy of a finite solenoid can be written as the energy of a long solenoid multiplied by a correction factor, K(R), called the Nagaoka factor [35,36] as shown in equation (25). A approximation for the Nagaoka factor correct to 6 significant figures which is straightforward to implement is given in ref.…”

“…The microscope has a liquid helium cooled in-column specimen stage equipped with coils to allow magnetic fields to be applied to the sample at any angle. This proved useful in the investigation of stacks of pancake vortices in YBCO (YBa 2 Cu 3 O 7-δ ) which apparently broke into several stacks as the angle at which the field was applied increased [25].…”