Determination of levitation force and pinning properties of (Sm123)_1−x(Yb211)_x bulk superconductor depending on Yb211 doping ratio

Abstract

The vertical force density curves of (Sm123)1−x(Yb211)x high temperature superconductor (HTS) samples prepared by a melt‐powder‐melt‐growth technique were measured during vertical and lateral traverses in zero field cooling (ZFC) regime for various doping levels (x). It was determined that the maximum vertical force density of the samples increases when the doping level increases and after certain level of the doping the force saturates. The pinning properties, which create attractive force, were enhanced up to a certain Yb211 doping level by introducing locally suppressed superconducting regions. These results indicate that the optimization fabrication conditions and Yb211 doping level should be further investigated for larger dimensional samples to enhance technological applicability. The frozen image model was used to predict the experimentally measured levitation force between a permanent magnet (PM) and the superconductor samples. Various configurations of the PM/HTS force interaction were tested according to the magnet and superconductor size. The doped HTS samples do not show very strong diamagnetic behavior as the frozen image model predicts. The levitation force behavior regarding the dimensions of the PM and HTS indicates an illustration how the diamagnetic behavior of the superconductor transforms into the flux pinning.

Comparative study of critical current density, pinning force and levitation force behavior in Yb211 doped-Sm123 bulk superconductors

“…Following this procedure, Yb211-doped and undoped powders are pressed into a pellet form with 13 mm in diameter under 400 MPa pressure. Then, to understand whether the reheating temperature and cooling speeds have an effect on superconducting levitation force or not (Sm123)1−x(Yb211)x samples are heated to 1170 • C (reheating temperature) which is different than our earlier produced Sm123 samples [26]. After that, the samples were held at this temperature for 15 min and cooled down to 980 • C at the speed of 1.7 • C/min.…”

“…Therefore, the understanding and control of the microstructure are attractive challenges to enhance the superconducting properties of MPMG-processed Sm123 sample. Our previous studies indicated that the doping of Yb211 (Yb 2 BaCuO 5 ) into the Sm123 superconductor sample increases the value of the vertical magnetic levitation force [26]. The main objective of this study is to determine the relations between critical current density, volume magnetic pinning force, magnetic levitation force (in zero field cooling regime) and pinning mechanism of the bulk superconductor samples with nominal composition of (Sm123) 1−x (Yb211) x depending on non-superconducting Yb211 doping ratio x, varying from 0.00 to 0.35.…”

Levitation and guidance force efficiencies of bulk YBCO for different permanent magnetic guideways

“…Although some advancements have been achieved in improving the flux pinning ability and critical current density of HTS [11,12], the levitation [13] and guidance force values of HTS Maglevs are still mostly far from the technological applications. Also the production cost is very important issue to be taken into account for industrial application in Maglev systems.…”

Levitation force at different temperatures and superconducting properties of nano-structured MgB2 superconductors

“…Studies on bulk high temperature superconductors (HTS) indicate that the properties such as trapped magnetic field, magnetic levitation force and critical current density can be improved considerably by introducing nanometer-scale weak superconducting regions and by improving material processing techniques [12,13]. Since the discovery of superconductivity in bulk MgB 2 , it has been proposed as an alternative to HTS for these applications as, despite its lower critical temperature of 39 K, it has superior mechanical and superconductive properties.…”