Influence of temperature on levitation characteristics of the system CC tapes – Permanent magnets at lateral displacements

Abstract

For the development of levitation bearings and transport systems based on coated conductor (CC) tapes, it is essential to know not only information about the levitation force during vertical displacement, but also the stability of the system under lateral displacements of a superconductor relative to permanent magnets, as well as the effect of temperature on the lateral and vertical forces.In this paper, we present new experimental results of effect of temperature on levitation and lateral forces of CC tape stacks subjected to cyclic lateral displacements relative to the position of the permanent magnet (PMG). For the measurements, we used a 12 mm wide commercially available CC tape manufactured by Sunam. The tape was cut into 12 × 12 mm squares and stacked in stacks of 10, 30, and 50 elements. The measurements were carried out in both zero-field cooling mode (ZFC) and field cooling mode (FC). After the cooling procedure, cyclic lateral movements of the superconductor over the permanent magnet were performed. Measurements of the vertical and lateral components of the force of interaction between the stack of CC tapes and PMG were performed. The measurements were carried out at various superconductor temperatures in the range 33–77.4 K.The experimental results allow us to conclude that both the levitation force and lateral restoring force decrease with increasing temperature. An evident hysteresis of the vertical and horizontal components of the levitation force is noticeable. The hysteresis decreases with an increasing number of elements in the stack and increases with increasing temperature up to 77.4 K.