Objective:
-To show the perfect diamagnetism (repulsion of magnetic fields) in a superconductor.
Apparatus:
- YBCO superconducting disk
- small neodymium magnet
- plastic tweezers
- petri dish
- liquid nitrogen
- small dewar
Method:
Place the YBCO disk in the petri dish and place the neodymium magnet on top. The magnet will sit in contact with the YBCO. Now pour liquid nitrogen into the petri dish, enough to cover the surface of the YBCO. Once the YBCO becomes superconducting, the magnet will levitate on top. To highlight the levitation, and the fact that the magnet will be “locked” in place, spin the magnet above the superconductor using the tweezers. Note that you may need to “help” the magnet up with the tweezers.
Notes:
- The only department on campus regularly using liquid nitrogen is forensics. Liquid nitrogen can be ordered, but is slightly expensive due to the extra nitrogen required to cool down the dewar. To use this demo, you can consult Michael for nitrogen delivery.