Christoph Beyer

Superconductively levitated transport system - the SupraTrans project

SupraTrans is an innovative transportation concept based on the principle of superconductive magnetic levitation. The aim of the project is to create a fully working prototype, which proves its ability for passenger transport by explicit consideration of the compatibility between systems for propulsion, safety, positioning, power supply, transport logistics and the levitation system itself. The SupraTrans technology uses the flux pinning in high temperature superconductors (HTS) to stabilize the lateral and vertical position of the vehicle on the magnetic track. This self-stabilizing system is the main advantage of the superconductive levitation in comparison to all other levitation systems, which need electronic control and power to keep a constant distance between the train and the track.

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

After the levitation force relaxation was studied for different field-cooling height and working-levitation height, the high-temperature superconductor (HTS) bulk was horizontally moved in the lateral direction above the permanent magnet guideway. Both levitation and guidance force were collected by the measurement system at the same time. It was found that the decay of levitation force is dependent on both the maximum lateral displacement and the movement cycle times, while the guidance force hysteresis curve does not change after the first cycle. This work provided scientific analysis for the HTS maglev system design.

Static and Dynamic Behavior of a Superconducting Magnetic Bearing Using YBCO Bulk Material

The technical progress in the manufacture of high temperature superconducting bulk material (HTS) provides various possible applications. These include non-contact linear transport systems and frictionless rotating bearings using the pinning effect in Type-II superconductors. During the last five years, a group of industrial and research partners have developed an innovative magnetic levitation system (SupraTrans) with a permanent magnetic rail and YBCO superconducting bulks in the vehicle. To optimize the levitation and guidance system, further investigations in the static and dynamic behavior have been accomplished and are reported. Comparisons between the statics and the dynamics show a very good agreement in all comparable parameters.

Formation and destruction of cube texture in MgO films using ion beam assisted pulsed laser deposition

Biaxially textured MgO thin films were deposited on amorphous substrates using ion beam assisted pulsed laser deposition. The development of the texture and microstructure was investigated with electron diffraction and atomic force microscopy. After the first few nanometers of growth, a sharp nucleation texture is observed. During further growth a texture change takes place, leading to two texture components, one in the 〈220〉 direction and the other in the 〈111〉 direction parallel to the substrate normal. In both cases the 〈200〉 direction is parallel to the ion beam. This texture change can be explained in terms of the highly anisotropic sputter rate observed in experiments on single crystals, leading to grains having a 〈200〉 direction parallel to the ion beam during growth being preferred. Without ion beam assistance during further growth, one of the two texture components dominates.

A Turnout Switch for a Superconductively Levitated Linear Transport System

Within the SupraTrans project, a joint venture between research institutes, universities and industrial companies, a full working prototype of a superconductively levitated transport system has been constructed and developed. The levitation and guidance system is based on flux pinning in melt-textured bulk YBa2Cu3O7-delta (YBCO) that stabilizes the vertical and lateral position of the vehicle above the magnetic track. In contrast to conventional electromagnetic Maglev systems, track and vehicle do not mechanically envelop each other in the superconducting Maglev. It is therefore possible, to construct a non-mechanical turnout switch using electromagnets. Such fast working turnout switches are essential to establish a highly branched transportation network. An experimental set-up for an electromagnetic turnout switch has been created for a toy sized model train. Investigations regarding levitation force and stiffness of the vehicle during several crossings have been performed. Thereby the ideal line across the switch has been used to measure vertical and lateral forces in every step of the movement. The evaluation shows a small delay but appropriate levitation and guidance behavior.

Guideway and turnout switch for the SupraTrans project

This paper will deliver insight into technology and physics of the levitation system for the SupraTrans project, a prototype of a superconducting transportation system. The technology used herein bases on the flux pinning in melt-textured bulk YBa2Cu3O7-X (YBCO) that stabilizes the lateral and the vertical position of the vehicle above the magnetic track. A track made from permanent magnets and soft magnetic steel-yokes acting as flux collectors has been designed and its capability is presented. The concept also includes a fast electromagnetic turnout switch to establish a highly branched transportation network.

Development of Texture and Microstructure in MgO Buffer Layers Using Ion-Beam Assisted Pulsed Laser Deposition

MgO thin films were deposited on amorphous substrates using ion-beam assisted pulsed laser deposition. The texture formation was investigated in-situ with RHEED. The microstructure of the films was observed by AFM. Using an ion beam at an angle between 35° and 65° with respect to the substrate normal, strong nucleation textures develop. Under certain deposition parameters a cube texture is observed in films thinner than 10nm. During further growth this nucleation texture changes in such a way that the «100» direction becomes parallel to the ion beam. This change can be explained by the anisotropic sputter rate of MgO seen in sputter experiments on single crystals. Moreover, MgO films were deposited homoepitaxially on MgO single crystals above 250° C with internal stresses decreasing with increasing deposition temperature. In contrast, films grown further on the thin cube-textured nucleation layer without ion-beam assistance show a texture change towards fibre textures.

Formation of Biaxially Textured MgO Buffer Layers using Ion-Beam Assisted Pulsed Laser Deposition

MgO thin films were deposited on amorphous substrates using ion-beam assisted pulsed laser deposition. The texture formation was investigated in-situ with RHEED. The microstructure of the films was observed by AFM. Using an ion beam at an angle of 55° with respect to the substrate normal, strong nucleation textures develop. Above 250°C a cube texture is observed in films thinner than 10 nm. During further growth this nucleation texture changes in a way that the direction becomes parallel to the ion beam. This change can be explained by the anisotropic sputter rate of MgO found in sputter experiments on single crystals. Moreover, MgO films were deposited homoepitaxially on MgO single crystals above 250°C with internal stresses dreasing with increasing deposition temperature. This result gives rise to hope that homoepitaxial growth of MgO on the nucleation layer without ion-beam assistance should be possible in future PLD-experiments keeping the desired cube texture in thicker films.