Oxygen defects relaxation in high-temperature YBa _2Cu _3O _7 superconductors (Conference Paper)

摘要

The temperature dependences of normal state static magnet susceptibility χ(T) for high-temperature YBa _2Cu _3O _7 superconductors (T _c ≤ T ≤ 400 K) measured for the same sample before and after 22 years of storage are compared. It is shown that during longime storage of a maximally doped sample, its electronic system is more in equilibrium than it was in the initial state, while a similar underdoped sample decomposed completely. Comparing the χ(T) curves for YBa _2Cu _3O _7, we draw conclusions as to the nature of the Curie contribution and the fluctuation-induced contribution to the magnetic susceptibility of the investigated sample, and the experimental procedure for determining T _c.