Concepts

Superconductivity

Overview

A NdBFe magnet levitates above a high T_c superconductor when it is superconducting.

Details

Equipment

• [1] YBaCuO superconductor with yellow tape on top (for visibility)
• [1] Small NdBFe magnet
• [1] Petri dish
• [1] Foam support
• [1] Pair of plastic forceps
• [1] Small wire hoop
• [1] Foam cup
• [1] Video camera
• [1] Small (~2 L) dewar of liquid nitrogen

Safety Equipment

• [1] Safety goggles
• [2] Safety glove

Classroom Assembly

1. Place the petri dish on the foam support.
2. Place the superconductor in the petri dish.
3. Center the NdBFe manget on the superconductor using the forceps.

Important Notes

• Liquid nitrogen can cause frostbite, blindness, and asphixiation. Handle with care in well-ventilated areas.
• The superconductor is a ceramic containing heavy metals, which are poisonous. Wash your hands after use.
  
• The superconductor is a brittle ceramic. Handle with care.
• The magnet is strong. Handle with care.

Script

1. Put on gloves and goggles.
2. Pour liquid nitrogen into the petri dish until the superconductor is fully submerged.
3. Continue to add liquid nitrogen as it boils off. When the superconductor reaches critical temperature (~90 K), it will superconduct and the magnet will levitate. Be patient; this can take a while.
4. Spin the magnet with the forceps.
5. Pass the wire hoop around the magnet to show it is levitating.
6. Gently push the magnet with the forceps to demonstrate its range of stability over the superconductor.

Additional Resources