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Title: FePd thin films as a replacement for FePt thin films as the hard bias magnet in the read head for hard disk drives
Author: Egan, Patrick W.
ISNI:       0000 0004 5372 5873
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2014
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Full text unavailable from EThOS. Thesis embargoed until 01 Dec 2019
The purpose of the research was commercial in that it was carried out to ascertain if the more expensive FePt thin film could be replaced by the more cost effective FePd thin film as the hard biasing magnet in the read head of a hard disk drive. Magnetron sputtering was used to deposit the thin films. The magnetic properties and crystal structure of both FePd alloy thin films and FePd multilayers were investigated using VSM, B-H Looper and XRD. Room temperature deposition together with post annealing and heated substrate deposition of both the FePd alloy and FePd multilayers was carried out. In addition the effect of seed layers, seed layer thickness and the effect of heated deposition on the grain size was also studied. The magnetic properties and crystal structure of FePd alloy thin films and the Fe/Pd multilayer thin films are affected by the deposition temperature, seed layers and seed layer thickness and also by the thickness of the Fe and Pd layers in the Fe/Pd multilayer. FePd alloy and Fe/Pd multilayer thin films were produced with in-plane magnetisation and a saturation magnetisation of 1T or better but none of the films produced have a coecivity of 3500 Oe. The 36nm Fe50Pd50 alloy film with an Bnm Ru seed layer deposited at a temperature of 450°C showed the largest He of 2500 Oe but with an Ms of only 0.79T. Therefore the FePd thin film alloy or multilayers were unable to produce the required He. FePd thin films are therefore not a viable replacement for the FePt thin films currently used as the hard biasing magnet in the read head of HDD. Similarly the temperatures used to produce the FePd films with the largest He values are too high for the read head manufacturing process, because temperatures above 350°C would cause other layers in the read head to degrade.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available