Positron annihilation studies of high Tc superconductors

This paper reports on the Positron annihilation technique which has emerged as a powerful, nondestructive solid state tool in the hands of solid state physicists for studying electronic properties, defects associated with materials. There are different experimental techniques available to investigate the behaviour of positrons in solids. These are Positron lifetime, Doppler broadening and Angular correlation of the annihilated radiation. Positron lifetime measurement gives us a valuable parameter to get specific informations regarding the electron density at the annihilation site, by which one can interpret the structural defects. Doppler broadening of annihilation is a fast and accurate method to know the characteristics of crystalline defects. Positron angular correlation measurement affords details regarding the electronic properties such as Fermi surface, band gap etc