Relaxation processes in optically excited high-Tc films

✍ Scribed by A.M. Kadin; P.H. Ballentine; W.R. Donaldson

• Book ID: 104356428
• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 361 KB
• Volume: 165-166
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/s0921-4526(09)80339-6

✦ Synopsis

We have observed the transient electrical response of current-biased YBa2Cu307 films irradiated with 150 ps pulses from a Nd:YAG laser (A=1.06I!m). The magnitude of the response always agrees quantitatively with a simple heating model, as does the speed of the response «2 ns) in optically thin films «=0.2I1m). However, an equally rapid response in some thicker films is faster than thermal diffusion through the film can explain. At low temperatures «20 K), this rapid response provides indirect evidence for nonequilibrium hot-electron transport across the film on the 1 ps timescale. At higher temperatures, a similarly fast response can be achieved only by biasing the film close to the critical current, where rapid current redistribution can account for the results.