Properties of Superconductors

- Overview

A superconductor is a material that conducts electricity with zero resistance. This means that when a conductor becomes a superconductor below its critical temperature, no energy is lost to heat, sound, etc. Most materials should be at extremely low temperatures to become superconductors. 

Research is currently underway to find materials that behave like semiconductors at higher temperatures. Currently, when making semiconductors, too much energy is wasted in the cooling process, making it inefficient and uneconomical.

- Property 1: Critical Temperature/Transition Temperature

The temperature below which the material changes from a conductor to a superconductor is called the critical temperature (Tc) or transition temperature. 

Critical temperature (Tc), or the temperature at which a material acts as a superconductor, is an important issue. The transition from conductor to superconductor is sudden and sweeping.

For most materials, temperatures between absolute zero and 10 Kelvin, or -273 degrees Celsius to -263 degrees Celsius, are too cold to be practical. The subsequent focus was on finding materials with higher Tc.

- Feature 2: Zero Resistance/Infinite Conductivity

In the superconducting state, the material has zero electrical resistance. When the temperature of a material drops below its critical temperature (Tc), its electrical resistance suddenly decreases to zero. Mercury is an example of a superconductor, exhibiting zero resistance below 4 Kelvin.

Superconductors are solids that exhibit zero resistance to the flow of electric current at low temperatures, a phenomenon known as superconductivity. The temperature at which the electrical resistance of a substance drops to zero is its superconducting transition temperature (Tc). 

Superconductors also expel magnetic fields from their interiors, a phenomenon known as the Meissner effect. 

Superconductivity can be explained by the BCS theory, which states that electrons are able to move through solids without resistance because they couple to form pairs of electrons (Cooper pairs). High-temperature superconductors have Tc values greater than 30 K.

- Feature 3: Expulsion of Magnetic Field

Below a critical temperature, a superconductor does not allow magnetic fields to penetrate its interior. This phenomenon is called the Meisser effect.

The Meissner effect, the expulsion of the magnetic field from within a material that is becoming a superconductor, loses its resistance to the flow of electric current when cooled below a certain temperature (often called the transition temperature). close to absolute zero. The Meissner effect is a property of all superconductors and was discovered in 1933 by German physicists W. Meissner and R. Ochsenfeld. 

- Property 4: Critical Magnetic Field

The certain magnetic field value at which the superconductor returns to the conductive state is called the critical magnetic field. The value of the critical magnetic field is inversely proportional to temperature. As the temperature increases, the critical magnetic field value decreases.

 [More to come ...]