Stability studies of Hg implanted YBa 2Cu 3O 6+x

Abstract

High quality YBa 2Cu 3O 6+ x (YBCO) superconducting thin films were implanted with the radioactive 197mHg ( T 1/2=24 h) isotope to low fluences of 10 13 atoms/cm 2 and 60 keV energy. The lattice location and stability of the implanted Hg were studied combining the Perturbed Angular Correlation (PAC) and Emission Channeling (EC) techniques. We show that Hg can be introduced into the YBCO lattice by ion implantation into a unique regular site. The EC data show that Hg is located on a highly symmetric site on the YBCO lattice, while the PAC data suggests that Hg occupies the Cu(1) site. Annealing studies were performed under vacuum and O 2 atmosphere and show that Hg starts to diffuse only above 653 K.