Superconductivity

Definition

Superconductivity is a quantum mechanical phenomenon where certain materials exhibit zero electrical resistance and expulsion of magnetic fields when cooled below a critical temperature. This state allows for the unimpeded flow of electric current.

5 Must Know Facts For Your Next Test

1. Superconductors have zero electrical resistance below their critical temperature, allowing for perfect conductivity.
2. The Meissner effect in superconductors results in the expulsion of magnetic fields from their interior.
3. Type I superconductors have a single critical magnetic field, whereas Type II superconductors have two critical fields and can allow partial penetration of magnetic flux.
4. BCS theory explains superconductivity through the formation of Cooper pairs, which are bound pairs of electrons with opposite spins and momentum.
5. High-temperature superconductors operate at higher critical temperatures than conventional superconductors, often above the boiling point of liquid nitrogen (77 K).

Review Questions

• What happens to the electrical resistance of a superconductor when it is cooled below its critical temperature?
• Describe the Meissner effect in superconductors.
• How do Type I and Type II superconductors differ in terms of their magnetic properties?

Related terms

Critical Temperature: The temperature below which a material becomes superconductive and exhibits zero electrical resistance.

Meissner Effect: The phenomenon where a superconductor expels all internal magnetic fields as it transitions into the superconducting state.

Cooper Pair: A pair of electrons bound together at low temperatures in a superconductor, responsible for carrying electric current without resistance.