Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362729
Title: Pulsed laser deposition of electronic ceramics and analysis of the ablation plume
Author: York, Timothy Howard
ISNI:       0000 0001 3575 4740
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 1996
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Abstract:
Thin film growth by pulsed laser deposition, (PLD) is a technique, which has been investigated for over thirty years but has come to prominence more recently in the growth of complex multicomponent materials. These materials include several technologically important perovskite structured compounds that display high temperature superconductivity or ferroelectricity and are difficult to process into high quality thin films. Despite the enormous range of thin films and multilayers that have been deposited by PLD, many of the physical processes involved during the transfer of material from target to substrate are not well understood. The aim of this project is twofold: 1. To study the energy and mass distribution of ions ablated from the target surface by the laser pulse under similar conditions to those found in PLD with a view to using this technique to better understand PLD and as an in situ diagnostic method during PLD. 2. To briefly investigate the ideal growth conditions of lead zirconate titanate, PZT. This allows the data from the plume to be examined in the context of thin film deposition rather than simply in the context of laser ablation or desorption. The ion mass and energy spectra in the plume are obtained by placing an electrostatic cylindrical mirror analyser in tandem with a quadrupole mass spectrometer where the substrate would normally be in PLD. The former filters out all but a narrow "kinetic energy window" in the ions while the latter passes only a narrow range of masses. The method can give inconsistent and spurious results which are difficult to identify; the conditions under which these results occur are laid out and a procedure to avoid them is shown. The laser source used is mainly a Q-switched, frequency doubled Nd:YAG operating at a wavelength of 532nm although a frequency quadrupler (266nm) is used for some of the later deposition work. The thesis concentrates on electroceramics as these materials are both interesting from a technical and scientific point of view and also because many of the materials most successfully deposited by PLD fall into this general category. Other materials such as carbon and iron are investigated mainly to contrast their behaviour with that of the principle group, that of electroceramics. The ceramic compounds studied include PZT ( lead zirconate titanate), cerium oxide and the high temperature superconductors Bi2Sr2Ca2Cu3O10 which has a critical temperature of 110K, and also YBa2Cu3 O7.δ which has a critical temperature of 90K is briefly mentioned.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.362729  DOI: Not available
Keywords: Thin films; Ceramic superconductors
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