9-13 July 2012
Africa/Johannesburg timezone
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Room Temperature FePt Nanoparticles Formation Kinetics during Laser Solution Photolysis

Presented by Mr. Steven NKOSI on 10 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track A - Division for Condensed Matter Physics and Materials

Abstract

Ultra-small spherical and highly polycrystalline particles of FePt were synthesized with d-spacing of about 2.50 Angstroms. The effect of ultra-violet laser on temperature and chemical process on FePt nanoparticles formation during photolysis was investigated. During the laser irradiation, temperature measurements were performed using an infrared GOBI camera. It was found that there are no significant temperature changes during laser irradiation of the precursor. The measured temperature was found to be 300 K ± 001 K. This was comparable with the temperature of the background temperature. The FePt nanoparticles formation which is based on resonant and selective bond dissociation are due to an effect of laser pressure and photo-chemical process. The presented energy-balance equation first from Haggerty & Cannon (1981) and also modified by Mwakikunga et al. (2011) was modified to new energy-balance equation to suit our results. From this newly modified equation it was found that the creation of positive of ion is linear with UV laser intensity whereas the electrons prove to have more uncertainties. From the theory fit of the new energy-balance equation to the experimental data for positive ions and electrons, the parameters enthalpy of dissociation of FePt was found to be 9.006E-6 J/mol and 8.375E-6 J/mol respectively. Prior to laser photolysis, the fit suggest that the solution contains few ions 0.15671 ± 0.0107 and 0.08828 ± which were attributed to the background light. The effect of background light on positive ions and electrons creation was also quantify to be 1.6238 ± 0.1113E-12 J/mol and 0.8500E-12 J/mol respectively.

Award

Yes

Level

PhD

Supervisor

Bonex Mwakikunga and bmwakikunga@csir.co.za and CSIR DST/NCNSM Pretoria

Paper

Yes

Place

Location: IT Building
Room:


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