Hi Ron,
Here is the page from Tel Aviv University: http://www.tau.ac.il/~supercon/ It is likely that the white disc is a composite sandwich of materials which is mostly (90%) merely a thermal insulator - possibly a white cloth or foam of some kind holding a 'supply' of LN for an extended time of operation. You can see a layer of the cloth which has become loosened in the video. Y123 is very dark in color as you know. Since the Group claims to specialize in making high quality 2-3" dia YBCO wafers, which are deposited on top of Sapphire in thin layers we can assume that the 'real' disc is thin and seen at the bottom, and most of the apparent volume which is seen is the white insulator material, giving the appearance of much more mass than is there in actuality. Since the mass is low the angular momentum problems are minimal at low speed. In addition - and most importantly - they claim to deposit the thing films at different crystallographic orientations, and with doping. This could provide the properties that give the unusual departure from normal flux pinning. Quote: "Recent work, showed the possibility of making atomically flat a-axis grain of YBCO grown on top c-axis films" . this means to me that the Y123 is oriented in perpendicular regions on top of each other to provide the kind of stability which is seen. Jones From: Ron Kita Subject: [Vo]:Tel Aviv Superconductor- Levitation Greetings Vortex, I haven t had a chance look for the superconductor material used in the levitation video, but it seems like this is not the usual "flux pinning" as experienced by 1-2-3 SC materials: http://en.wikipedia.org/wiki/Flux_pinning Ron Kita, Chiralex Few people realize that when one spins a symmetical magnet as a ring magnet- the flux lines remain stationary in space. This is the principle of the One Piece Farady Homopolar Generator.
