The Superferritivity: A New Principle And Its Application To The Problems Of A Trumanting Charged, Magnetized Mass An Essay In Ferrotoroid Dynamics
Superconducting supercurrent is a quantum mechanical effect in superconducting materials which confers on them the ability to transport electrical current without resistance or other dissipative losses.
A supercurrent can exist in either type of superconducting material, either type in all three spatial dimensions, and be arbitrarily large within some limits, thus enabling superconductor applications.
Superconductivity was first reported in 1911 by Dutch physicist Heike Kamerlingh Onnes on mercury. German physicist Carl Wilhelm Oersted discovered the same phenomenon in 1820, but Onnes is usually given credit for discovering superconductivity.
Oersted left Dutch universities in 1844, having obtained all of his knowledge in this field from Onnes, who was a professor at Leiden University, where Oersted spent most of his life. Oersted was the first to demonstrate that a magnetic field can induce magnetization in a material lacking intrinsic magnetism; he realized that the Hall effect was the same effect as a magnetization, and proved that a changing magnetic field would generate a voltage without any conductor.
The free energy density in a superconducting material must be a minimum, except for a possible term that can offset this minimum. A superconducting state is not a magnetic state, but it is often described as a "magnetic" state because of the importance of magnetic fields.
Superconductivity is related to the recent discovery of high-temperature superconductivity. At approximately 100 K and pressures of 1 gigapascal (GPa), superconductors with a transition temperature Tc above 110 K have been discovered.
Josephson, proposed in 1957, describes the current-voltage characteristics of a current-biased junction of two superconductors. Josephson's law states that there is a phase difference of π/2 between two macroscopic wavefunctions separated by a junction. The Josephson voltage is given by the expression, u = I α t, where I is the critical current, α is the contact area, and t is the thickness of the junction.
Ons' findings were not widely recognized until shortly before World War II, when he and Dutch physicist Pieter M. van Alphen performed experiments in which they were able to measure and control the supercurrent, and later won the Nobel Prize for Physics in 0b46394aab