PT Unknown
AU Gol’tsman, GN
   Kouminov, PB
   Goghidze, IG
   Karasik, BS
   Gershenzon, EM
TI Nonbolometric and fast bolometric responses of YBaCuO thin films in superconducting, resistive, and normal states
SE Proc. SPIE
PY 1994
BP 81
EP 86
VL 2159
DI 10.1117/12.176133
DE YBCO HTS HEB; nonbolornetric
AB The transient voltage response in both epitaxial and granular YBaCuO thin films to 20 ps pulses of YAG:Nd laser radiation with 0.63 micrometers and 1.54 micrometers was studied. In normal and resistive states both types of films demonstrate two components: nonequilibrium picosecond component and following bolometric nanosecond. The normalized amplitudes are almost the same for all films. In superconducting state we observed a kinetic inductive response and two-component shape after integration. The normalized amplitude of the response in granular films is up to several orders of magnitude larger than in epitaxial films. We interpret the nonequilibrium response in terms of a suppression of order parameter by the excess of quasiparticles followed by the change of resistance in normal and resistive states or kinetic inductance in superconducting state. The sharp rise of inductive response in granular films is explained both by a diminishing of the crossection for current percolation through the disordered network os Josephson weak links and by a decrease of condensate density in neighboring regions.
ER