INTERACTION OF SUPERCONDUCTING Y1BA2CU3O7-X TARGETS WITH 1.064 MU-M Q-SWITCHED ND-YTTRIUM-ALUMINUM-GARNET LASER

Bulk superconducting targets of Y1Ba2Cu3O7-x were prepared and charact erized for resistance, structure, morphology, and composition. The tar gets were irradiated by a Q-switched 1.064 mu m wavelength Nd:yttrium- aluminum-garnet (YAG) laser having 20 ns pulse duration at 2.0 J/cm(2) (shot) energy density. A cumulative laser exposure of the target surf ace results in the formation of microscopic conical columnar structure s aligned parallel to the incident laser beam. Evolution of these stru ctures in the present case is attributed to the longer penetration dep th of optical radiation and localized material removal by microexplosi ons beneath the surface. Energy dispersive analysis by an x ray of the individual column shows microscopic phase segregation and erosion acc ompanied by shadowing as the primary cause of the cone formation proce ss. (C) 1998 Laser Institute of America. [S1042-346X(98)00201-0].