Laser-target interactions and its effect in controlling properties of laser-deposited superconducting thin films

Rajiv K. Singh, Deepika Bhattacharya, Paul H. Holloway

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The nature of evaporation/ablation characteristics during pulsed laser deposition strongly controls the quality of laser-deposited films. To understand the origin of particulates in laser deposited films, we have simulated the thermal history of YBa2Cu3O7 targets under intense nanosecond laser irradiation by numerically solving the heat flow equation with appropriate boundary conditions. During planar surface evaporation of the target material, the sub-surface temperatures were calculated to be higher than the surface temperatures. While the evaporating surface of the target is constantly being cooled due to the latent heat of vaporization, sub-surface superheating occurs due to the finite absorption depth of the laser beam. Sub-surface superheating was found to increase with decreasing absorption coefficient and thermal conductivity of the target, and with increasing energy density. The superheating may lead to sub-surface nucleation and growth of the gaseous phase which can expand rapidly leading to microexplosions and 'volume expulsion' of material from the target. Experiments conducted by us and other research groups suggest a strong relation between degree of sub- surface superheating and particle density in laser-deposited films.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherPubl by Int Soc for Optical Engineering
Pages45-56
Number of pages12
ISBN (Print)0819407283, 9780819407283
DOIs
StatePublished - 1992
Externally publishedYes
EventProgress in High-Temperature Superconducting Transistors and Other Devices II - San Jose, CA, USA
Duration: 12 Sep 199113 Sep 1991

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1597
ISSN (Print)0277-786X

Conference

ConferenceProgress in High-Temperature Superconducting Transistors and Other Devices II
CitySan Jose, CA, USA
Period12/09/9113/09/91

Fingerprint

Dive into the research topics of 'Laser-target interactions and its effect in controlling properties of laser-deposited superconducting thin films'. Together they form a unique fingerprint.

Cite this