Langmuir probe measurements and mass spectrometry of plasma plumes generated by laser ablation of La0.4Ca0.6MnO3

Abstract

Articles you may be interested inThe plasma formed in vacuum by UV nanosecond laser ablation of La 0.4 Ca 0.6 MnO 3 in the fluence range of 0.8 to 1.9 J cm À2 using both Langmuir probe analysis and energy-resolved mass spectrometry has been studied. Mass spectrometry shows that the main positive ion species are Ca þ , Mn þ , La þ , and LaO þ . The Ca þ and Mn þ energy distributions are quite broad and lie in the 0-100 eV region, with the average energies increasing with laser fluence. In contrast, the La þ and LaO þ distributions are strongly peaked around 10 eV. The net time-of-arrival signal derived from the measured positive ion energy distributions is broadly consistent with the positive ion signal measured by the Langmuir probe. We also detected a significant number of O À ions with energies in the range of 0 to 10 eV. The Langmuir probe was also used to measure the temporal variation of the electron density and temperature at 6 cm from the ablation target. In the period when O À ions are found at this position, the plasma conditions are consistent with those required for significant negative oxygen ion formation, as revealed by studies on radio frequency excited oxygen plasma. V C 2014 AIP Publishing LLC. [http://dx

Exploring fs-laser irradiation damage subthreshold behavior of dielectric mirrors via electrical measurements

“…Other reports focus on LP measurements of ablation threshold in the ns regime [ 22 ] , while reports on the detection of the fs-incubation stage emphasize the necessity of having a minimum of 10,000 pulses to estimate the threshold [ 23 ] . In general, the data available in the literature regarding LP measurements concerns the dynamics of the charged particle above the ablation threshold at a large distance (over 2–3 cm) from the target [ 24 ] . However, as the LP technique is based on charge collection, it could be promising for subthreshold measurements.…”

Manipulation of ion energies in pulsed laser deposition to improve film growth

“…Focusing ions with the grid will, hence, increase the number of ions analysed, but not necessarily the total number. A detailed description of the ion energy analysing system can be found elsewhere [46]. Due to the long distance of ion detection and continuous neutralization of ions during expansion, the ionic species in the plume were found to be mainly consisting of TiO + , while O + and Ti + showed very weak signals (bond energy TiO ≈ 6.9 eV, O 2 ≈ 5.3 eV) [47].…”