ülijuhtivad

Ülijuhtivad is the Estonian word for "superconducting". Superconductivity is a phenomenon observed in certain materials when they are cooled below a critical temperature. In this state, these materials exhibit two key properties: zero electrical resistance and the expulsion of magnetic fields.

When a material becomes superconducting, electricity can flow through it indefinitely without any loss of energy due to resistance. This means that once a current is established in a superconducting loop, it will continue to flow forever, provided the material remains below its critical temperature. The second characteristic, known as the Meissner effect, describes how magnetic fields are expelled from the interior of a superconductor. If a magnet is brought near a superconductor, the superconductor will repel it, causing the magnet to levitate above the surface.

The discovery of superconductivity dates back to 1911, when Dutch physicist Heike Kamerlingh Onnes observed it in mercury. Since then, superconductivity has been found in a wide range of materials, including elements, alloys, and complex ceramic compounds. These materials are often categorized into Type I and Type II superconductors, with Type II materials generally exhibiting superconductivity at higher temperatures and critical magnetic fields, making them more practical for technological applications.

The unique properties of superconductors have led to numerous potential and existing applications. These include powerful electromagnets used in MRI machines, particle accelerators, and high-speed magnetic levitation (maglev) trains. They also have potential uses in energy transmission, quantum computing, and sensitive magnetic field detectors. Research continues to focus on discovering materials that superconduct at even higher temperatures, ideally at or above room temperature, which would revolutionize many areas of technology and science.