Magnetic interaction force between high-Tc superconductor-ring and magnet

Abstract

1665 0.5 0.4 0.3 h z 0.2 W 0 0.1 t Y 2 0.0 -0.1Abstract-The magnetic interaction force between a superconducting ring and cylindrical permanent magnets of different lengths, aligned coaxially, has been investigated experimentally at zero-field-cooled and field-cooled conditions. The force as a function of the position of the magnet relative to the superconductor ring is qualitatively that expected if the superconductor is regarded as a diamagnet with non-ohmic dissipation. The hysteretic behavior of the axial force component was studied. It is shown that the size of the hysteresis loop grows with the strength of the magnet in general, but the shape of the loop also undergoes complicated changes. It was found that field-cooled conditions can yield a higher support force in this permanent magnet and superconducting ring system, with lower hysteresis loss. This makes this system an attractive candidate for a low loss magnetic journal bearing.

Mechanics of a magnet and a Meissner superconducting ring at arbitrary position and orientation

“…The axial force is enhanced with respect to the axially centered case (x = 0,y = 0). This behaviour is similar to that found experimentally by Ma et al [9]. Although Ma et al located nominally the magnet at the z-axis-corresponding to our Fig.…”

“…A non-ferromagnetic rotor may be attached axially to the magnet while the superconducting ring constitutes the stator. Axial forces between a superconducting ring and a magnet aligned to and located at its axis were measured by Ma, Postrekhin Ye and Chu in 2001 [9] . They found a maximum for the magnet at the border of the ring, a minimum for the magnet at the center of the ring and oscillations of the force with the axial position.…”

Superconductors and Lenz’s law

“…Questions on the inconsistency between the Meissner effect and Lenz's law or whether superconductors abide by Lenz's law have sometimes been raised [9][10][11][12][13], but there has as yet been no well-agreed explicit answer. Studies on the interaction between a magnet and a superconducting ring have mainly focused on the properties of a journal bearing constructed with a magnet and a high-temperature superconductor (HTS) bulk or ring [14][15][16], the outcomes from which are never able to answer the above question.…”

Force Analysis of a Permanent Magnet and a Superconducting Hollow Cylinder

“…This system was subject to many theoretical and experimental investigations within the last few years which makes it of special interest. Ma et al [4], studied experimentally the levitation force between superconducting ring and cylindrical magnet. They concluded that the ring shaped SC/PM system is an attractive candidate for low loss magnetic bearing.…”