Stability studies of Hg implanted YBa_2Cu_3O_6+x

摘要

High quality YBa_2Cu_3O_6+x (YBCO) superconducting thin films were implanted with the radioactive ~197mHg (T_1/2=24) 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 higly 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. direct c 1999 Elsevier Science B.V. All rights reserved.