Spin Motion of a Levitated Magnet Caused by Vertical Excitation of a High-Tc Superconductor

2002 ◽  
Author(s):  
Toshihiko Sugiura ◽  
Shuuichi Hayakawa ◽  
Tsuyoshi Tanaka ◽  
Masatsugu Yoshizawa
Keyword(s):  
Harmonic Balance ◽  
Magnetic Force ◽  
Vertical Direction ◽  
Spin Torque ◽  
Spin Motion ◽  
High Tc ◽  
Vertical Excitation ◽  
High Tc Superconductor ◽  
Method Of Harmonic Balance ◽  
Magnetic Center

This research deals with nonlinear dynamics of a permanent magnet freely levitated above a high-Tc superconductor excited in the vertical direction, focusing on generation of spin torque acting on the magnet. Equations of 6 d.o.f motion, nonlinearly coupled by magnetic force and torque, were described on the assumption that a magnet has an eccentricity between the center of gravity and the magnetic center. Force and torque were evaluated analytically by the flux frozen method. Dynamic behavior of the magnet was examined numerically for different frequencies of excitation. A simplified 2 d.o.f. system with only essential terms was introduced in order to discuss the mechanism of nonlinear coupling which generates spinning from vertical oscillation. Spinning motion of the magnet was examined in detail analytically by the method of harmonic balance. Experiments of vertical excitation were also carried out. Experimental results were compared with numerical ones.

Combination Resonance of a Magnet Over a High-TC Superconductor Excited Vertically

2001 ◽  
Author(s):  
Toshihiko Sugiura ◽  
Masayuki Kondo
Keyword(s):  
Magnetic Force ◽  
Vertical Direction ◽  
Vertical Motion ◽  
Mirror Image ◽  
Image Method ◽  
Combination Resonance ◽  
Nonlinear Functions ◽  
High Tc ◽  
High Tc Superconductor ◽  
Oscillation Modes

Abstract This research deals with nonlinear dynamics of a permanent magnet freely levitated above a high-Tc superconductor (HTSC) excited in the vertical direction. Magnetic force and torque can be evaluated analytically by the advanced mirror image method as nonlinear functions of both displacement and roll angle of the magnet. Equations of 3 d.o.f. motion show that the magnet has two oscillation modes due to linear coupling of the horizontal and roll motions. The both modes can be excited by nonlinear coupling with vertical motion when the superconductor is exited vertically in the neighborhood of the sum of the natural frequency of each mode. Frequency response of this combination resonance was numerically simulated. This resonance was also observed in experiments.

The vertical magnetic force and stiffness between a cylindrical magnet and a high-Tc superconductor

1994 ◽  
Vol 234 (1-2) ◽  
pp. 108-114 ◽  
Author(s):  
Anjali B. Riise ◽  
Tom H. Johansen ◽  
Harald Bratsberg
Keyword(s):  
Magnetic Force ◽  
High Tc ◽  
High Tc Superconductor

High resolution STEM imaging study on high Tc superconductor YBa2CuaO7-x

1988 ◽  
Vol 46 ◽  
pp. 882-883
Author(s):  
H.-J. Ou ◽  
J. M. Cowley
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Grain Boundary ◽  
Strong Field ◽  
Imaging Study ◽  
Structure Defects ◽  
High Tc ◽  
High Tc Superconductor ◽  
Diffraction Patterns ◽  
Lattice Planes

Using the dedicate VG-HB5 STEM microscope, the crystal structure of high Tc superconductor of YBa2Cu3O7-x has been studied via high resolution STEM (HRSTEM) imaging and nanobeam (∽3A) diffraction patterns. Figure 1(a) and 2(a) illustrate the HRSTEM image taken at 10' times magnification along [001] direction and [100] direction, respectively. In figure 1(a), a grain boundary with strong field contrast is seen between two crystal regions A and B. The grain boundary appears to be parallel to a (110) plane, although it is not possible to determine [100] and [001] axes as it is in other regions which contain twin planes [3]. Following the horizontal lattice lines, from left to right across the grain boundary, a lattice bending of ∽4° is noticed. Three extra lattice planes, indicated by arrows, were found to terminate at the grain boundary and form dislocations. It is believed that due to different chemical composition, such structure defects occur during crystal growth. No bending is observed along the vertical lattice lines.

Electron-Probe Quantitative Energy-Dispersive Analysis of Trace Magnesium Concentrations in Ag-Mg Alloys

1996 ◽  
Vol 54 ◽  
pp. 510-511
Author(s):  
R. B. Marinenko
Keyword(s):  
Electron Probe ◽  
Energy Dispersive Spectrometry ◽  
Mg Alloys ◽  
Energy Dispersive ◽  
Energy Dispersive Analysis ◽  
High Tc ◽  
Alloy Wire ◽  
High Tc Superconductor ◽  
Eds Analysis ◽  
Superior Mechanical Properties

Internally oxidized Ag-Mg alloys are used as sheaths for high Tc superconductor wires because of their superior mechanical properties. The preparation and characteristics of these materials have been reported. Performance of the sheaths depends on the concentration of the magnesium which generally is less than 0.5 wt. percent. The purpose of this work was to determine whether electron probe microanalysis using energy dispersive spectrometry (EDS) could be used to quantitate three different Ag-Mg alloys. Quantitative EDS analysis can be difficult because the AgL escape peak occurs at the same energy (1.25 keV) as the Mg Kα peak. An EDS spectrum of a Ag-Mg alloy wire is compared to a pure Ag spectrum in Fig. 1.

Evidence for magnetic organization of high Tc superconductor YBa 2 Cu8O7 observed by neutron diffraction

1987 ◽  
Vol 48 (10) ◽  
pp. 1623-1625 ◽  
Author(s):  
B. Farnoux ◽  
R. Kahn ◽  
A. Brulet ◽  
G. Collin ◽  
J.P. Pouget
Keyword(s):  
Neutron Diffraction ◽  
High Tc ◽  
High Tc Superconductor

Synthesis of One-dimensional Nano-sized Defects in High Tc Superconductor

2006 ◽  
Author(s):  
In-Gann Chen ◽  
Maw-Kuen Wu ◽  
Shih-Yun Chen
Keyword(s):  
High Tc ◽  
One Dimensional ◽  
High Tc Superconductor
Sign in / Sign up

Export Citation Format

Share Document