Internal magnetic relaxation in levitating superconductors

Influence of the lateral movement on the levitation and guidance force in the high-temperature superconductor maglev system

“…It has been accepted that the bulk superconductor is not in a really stable state after the drop; that is, the levitation force has a logarithmal decrease with time. [6][7][8] This phenomenon defined as levitation force relaxation has been investigated experimentally and theoretically. But most of their systems composed of the superconductor and magnet were coaxial 9 and there was no movement during the measurement.…”

Near-oscillatory relaxation behavior of levitation force in infiltration and growth processed bulk YBCO/Ag superconducting composites

“…The nature of these pinning forces might be such that the velocity of flux motion is nonuniform. We propose that a systematic change in relaxation rate in a near oscillatory manner could be due to switching over of the current structure from unipolar to bipolar [7] or multipolar one [8]. This shift from one type of current structure to another type occurs as the magnetization varies.…”

Elimination of magnetic relaxation in superconductors on approaching a ferromagnet

“…Probably for the first time it was noted in a classical paper on the flux creep [2] that the total magnetic flux in a superconductor does not change for a long time after a small reversal of the external magnetic field. This effect was studied later in more detail and formed the basis of reverse methods for stabilization of magnetization [3,4] and the levitation force [5][6][7]. It was shown that the reversal does not improve pinning, but causes the internal magnetic relaxation [6] when the magnetic flux is redistributed over the superconductor volume; however, the total flux, magnetization and the force remain unchanged.…”

“…This effect was studied later in more detail and formed the basis of reverse methods for stabilization of magnetization [3,4] and the levitation force [5][6][7]. It was shown that the reversal does not improve pinning, but causes the internal magnetic relaxation [6] when the magnetic flux is redistributed over the superconductor volume; however, the total flux, magnetization and the force remain unchanged. Suppression of the magnetization relaxation by a transverse ac magnetic field was studied in [8].…”