Electronic State Distributions of YBa₂Cu₃O_7-x Laser-Ablated Plumes

Abstract

The application of spectral and imagery diagnostics to YBa 2 Cu 3 O 7 (YBCO) laser-ablated plumes was systematically studied to determine their effectiveness for process control. Emission signatures were collected for plumes created by ablating bulk YBCO with a pulsed laser source. A KrF (λ=248 nm) laser source operating at 4-10 J/cm 2 at a 4-10 Hz pulse repetition frequency was used to ablate a bulk YBCO target at O 2 background pressures ranging from 50 to 400 mTorr. Emission spectra were collected over the 500 to 860 nm bandpass at distances from the target ranging from 31.4 to 55.0 mm. Of 87 observed emission lines, 76 were assigned to specific transitions with the aid of calibration lamps and reference to tables of energy levels. Line fluences were corrected for self-absorption, and electronic state distributions were calculated using the most recent NIST transition probabilities.