What Are Superconducting Ceramics

The positions of specimens marked 1a 1c 3a 3c used for the study of t c and j c b dependence in all samples are shown in fig.

What are superconducting ceramics.

Conductive ceramics conductive ceramics superconductors. Ceramic superconductors the ceramic materials used to make superconductors are a class of materials called perovskites. 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. Magnesium diboride mgb2 is known to be an important high temperature superconductor material.

That is it loses all resistance to electric current at extremely low temperatures. The discovery of high temperature above the temperature of liquid nitrogen ceramic superconductors has changed superconductivity from an interesting curiosity to a useable technology with particular applications in the medical field as a superconducting magnet in mri scanners. The temperature at which resistance ceases is referred to as the transition temperature or critical temperature tc. High energy ball milling with subsequent low temperature sintering remains an attractive solid state.

Superconducting ceramics having relatively high critical temperatures are composed of rare earth metals alkaline earth metals and copper. Its structure consists of three cubes with yttrium or barium at the centre copper at the corners and oxygen at the middle of each edge with the exception of the middle cube which has oxygen vacancies at the outer edges. They have few defects and a limited polycrystalline interfacial area. The majority of high temperature superconductors are ceramic materials.

Tc is usually measured in degrees kelvin k 0 k being absolute zero the. The superconductor we will be experimenting with is an yttrium y barium ba and copper cu composition. Superconductivity is the complete disappearance of electric resistance in materials that are cooled to extremely low temperatures. They are then called low temperature superconductors.

Ybco is a superconducting ceramic. On the other hand metallic superconductors usually work below 200 c. This transformation takes place through the carbonate which is very stable and decomposes at temperatures above 900 c. Ceramic superconductors can be prepared using an oxalate precursor 3 4 which can be transformed to the superconducting oxide by sintering and annealing.