Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/2226
Title: Ferromagnetic metal-polymer nanocomposites for magnetic sensing applications
Authors: Kwong, Ho-yin Anthony
Subjects: Pulsed laser deposition
Ferromagnetic materials
Nanostructured materials
Nanoparticles
Magnetoresistance
Hong Kong Polytechnic University -- Dissertations
Issue Date: 2008
Publisher: The Hong Kong Polytechnic University
Abstract: In this project, cobalt and polytetrafluoroethylene (PTFE) composite films were fabricated by Pulsed Laser Deposition technique (PLD) with the use of split target. The composition of the films was changed by varying the pulse irradiation ratio of the metal and polymer targets. The deposited samples consist of cobalt particles of sizes about 5 nm and irregular shaped PTFE particles of size larger than 200 nm in a well connected PTFE polymer matrix. The cobalt-PTFE composite films exhibit a room temperature magnetoresistance (MR) change of about 5% at 10 kOe. A significant enhancement of MR value to 6% was achieved at 20 K at 8 kOe. The blocking temperature of the sample was obtained to be about 90 K. Possible explanations of the observed experimental results are suggested. Cost-effective and simple magnetic sensor applicable in device industries prepared by this method is anticipated. Fabrication of cobalt nanoparticles has been successfully demonstrated by PLAL technique in 3 kinds of solvent with detailed discussions. Superhydrophobic PTFE thin films for fabricating self-cleaning surfaces were successfully fabricated by PLD technique. A large contact angle of about 170o and low sliding angle was achieved. Detailed discussions and explanations were presented. Fabrication of cobalt hydroxide nanoplatelets at room temperature by an innovative method, simply using sodium hydroxide (NaOH) solution to react with a PLD prepared pure cobalt thin film, was presented. The morphology of the nanoplatelets and the crystal structure were characterized. This method provides a simple, relatively fast and clean method to produce nano-sized cobalt hydroxide for using in real applications.
Description: xiii, 156 leaves : ill. ; 30 cm.
PolyU Library Call No.: [THS] LG51 .H577M AP 2008 Kwong
Rights: All rights reserved.
Type: Thesis
URI: http://hdl.handle.net/10397/2226
Appears in Collections:AP Theses
PolyU Electronic Theses

Files in This Item:
File Description SizeFormat 
E-thesis_Link.htmFor PolyU Users 162 BHTMLView/Open
b21898194.pdfFor All Users (Non-printable)8.06 MBAdobe PDFView/Open


All items in the PolyU Institutional Repository are protected by copyright, with all rights reserved, unless otherwise indicated. No item in the PolyU IR may be reproduced for commercial or resale purposes.