TITLE:
Measurements of Pulsed 532 nm Laser Breakdown Spectroscopy of Synthesized Magnetite Nanoferrofluid
AUTHORS:
Mohammad E. Khosroshahi, Maryam Tajabadi
KEYWORDS:
Laser-Induced Breakdown Spectroscopy, Second Harmonic Generation, SPION, Nanoferrofluid, Elements Ratio
JOURNAL NAME:
World Journal of Nano Science and Engineering,
Vol.8 No.3,
September
28,
2018
ABSTRACT: We describe the results of 532 nm
pulse laser-induced breakdown spectroscopy (LIBS) of two samples of magnetite nanoparticles
(SPIONs) nanoferrofluid synthesized at room (S1) and elevated temperatures (S2)
and at three different laser energy levels and pulse frequency. The size of
magnetite nanoparticles, size distribution, magnetic crystalline phase and
magnetization were analyzed and measured
using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD) and vibrating sample
magnetometry (VSM). The SPIONs showed a distribution between 4 - 22 nm with a peak about 12 nm and saturation
magnetization of about 65 emu/g. The Saha-Boltzmann analysis of spectra
for medium energy level (1050 mJ) yields plasma temperatures of (3881 ± 200) K
and (26,047 ± 200) K for Fe I and OV as the lowest and highest temperatures
respectively. A range of corresponding electron density (Ne-) of
(0.47 - 6.80) × 1020, (0.58 - 8.30) × 1020 and (0.69 - 9.96) × 1020 cm-3were determined at 860, 1050 and
1260 mJ respectively using the estimated CCD pictures. The results confirmed a
higher elements ratio for S1 than S2 and the signal intensity indicated a
non-linear behaviour as a function of pulse frequency with the maximum ratio
value at 3 Hz. At higher frequency of 6 Hz no such turning point was observed.
The highest and lowest temperatures corresponded to Fe I and OV respectively.
The LIBS technique can be utilized to study, characterize and determine the
elements ratio required in most applications involving the synthesizing
process.