Ceramic Superconductors Wiki

Bcs means whether or not the superconductivity is explained within the bcs theory.

Ceramic superconductors wiki.

Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. A lanthanum barium copper and oxygen compound with a critical temperature of 30k. Yba 2 cu 3 o 7 x was the first ceramic superconductor discovered with t c greater than liquid nitrogen temperature. Superconducting quantum interference device squid.

Any material exhibiting these properties is a superconductor unlike an ordinary metallic conductor whose resistance decreases gradually as its temperature is lowered even down to near absolute zero a superconductor has a. The temperature at which resistance ceases is referred to as the transition temperature or critical temperature tc. X y means material x doped with element y t c is the highest reported transition temperature in kelvins and h c is a critical magnetic field in tesla. The highest critical current density is achieved when x 0 so that the composition is yba 2 cu 3 o 7 but the material remains superconducting for values of x down to about 0 5.

The first high temperature superconductor was discovered in 1986 by ibm researchers bednorz and müller 3 6 who were awarded the nobel prize in physics in 1987 for their important break through in the discovery of superconductivity in ceramic materials. This superconductor has a critical transition temperature around 90k well above liquid nitrogen s 77k. The ceramic materials used to make superconductors are a class of materials called perovskites. The yttrium compound is somewhat unique in that it has a regular crystal structure while the lanthanum version is classified as a solid solution.

Tc is usually measured in degrees kelvin k 0 k being absolute zero the. Ceramics are normally insulators. The yttrium compound is often called the 1 2 3 superconductor because of the ratios of its constituents. Yttrium barium copper oxide ybco is a family of crystalline chemical compounds famous for displaying high temperature superconductivity it includes the first material ever discovered to become superconducting above the boiling point of liquid nitrogen 77 k at about 92 k many ybco compounds have the general formula y ba 2 cu 3 o 7 x also known as y123 although materials with other y.

Opened up the possibilities for new superconductors. The ceramic superconductors are also called high temperature or liquid nitrogen temperature superconductors. A ceramic superconductor was discovered by alex müller and georg bednorz. The high temperature superconductors are ceramic materials with layers of copper oxide spaced by layers containing barium and other atoms.

The table below shows some of the parameters of common superconductors. Superconductivity is the complete disappearance of electric resistance in materials that are cooled to extremely low temperatures. Conductive ceramics conductive ceramics superconductors. Many ceramic superconductors physically behave as superconductors of the second type.