Cover Image

The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures

Giant Magnetoresistance (GMR) refers to a phenomenon of a considerable drop in electrical resistance in ultrathin ferromagnetic/non-magnetic layers structure, when a sufficiently high magnetic field is applied to the structure. Since the first time it was observed in late 1980’s, this area of resear...

Full description

Saved in:
Bibliographic Details
Main Author: Khamis @ Subari, Nazimah
Format: Thesis
Language:English
Published: 2010
Subjects:
QC Physics
Online Access:http://eprints.utm.my/id/eprint/11369/1/NazimahKhamisSubariMFS2010.pdf
http://eprints.utm.my/id/eprint/11369/
Tags: Add Tag
No Tags, Be the first to tag this record!
id my.utm.11369
record_format eprints
spelling my.utm.113692018-05-30T04:27:11Z http://eprints.utm.my/id/eprint/11369/ The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures Khamis @ Subari, Nazimah QC Physics Giant Magnetoresistance (GMR) refers to a phenomenon of a considerable drop in electrical resistance in ultrathin ferromagnetic/non-magnetic layers structure, when a sufficiently high magnetic field is applied to the structure. Since the first time it was observed in late 1980’s, this area of research has attracted a very strong interest due to the deep fundamental physics and its promising technological potential especially in data storage industry. This dissertation discusses the magnetoresistance of ferromagnetic/non-magnetic multilayers fabricated using electron beam evaporation technique. The magnetoresistance value is studied towards the effect of compositional variance, a range of post deposited annealing temperature, and multilayer thickness in terms of number of repetition of the bilayer as well as the non-magnetic layer thicknesses. The results on compositional variance show as deposited Co/Cu/Ni gives the largest magnetoresistance value of 8.75% followed by Ni/Cu/Ni (5.85%), Co/Ag/Co (2.64%) and Ni/Ag/Ni (1.48%). These four ferromagnetic multilayers were given heat treatment with a range of elevating temperature. The temperature ranges between 200°C to 350°C, resulting the magnetoresistance of the above structures increases to 14.25%, 10.68%, 7.45% and 4.38% respectively. However, the thermal stability for each multilayer systems were degraded after further annealing at a temperature called the blocking temperature. From the investigation, it was found that the blocking temperatures (or the optimum annealing temperature) for Co/Cu/Ni, Ni/Cu/Ni, Co/Ag/Co and Ni/Ag/Ni were 280°C, 290°C, 310°C and 280°C respectively. The study of thickness dependence GMR, focus only on Co/Cu/Co structures. It was shown that in [Co/Cu/Co]n structures, the magnetoresistance increase as n increases from 1 to 20. Meanwhile, for Cox/Cuy/Cox structures, the magnetoresistance increases as y decreases from 15 nm to 1 nm with x is fixed at 6 nm. The X-ray diffraction study for the optimum structures shows peaks of Co, Cu, Ni and Ag which describe the multilayers are in the crystalline form. The atomic force microscopy (AFM) image analysis for Co and Cu thin films with elevated annealing temperature reveals that the higher the annealing temperature, the larger the grain size of the multilayer. The EDX spectrum analysis confirmed the presence of Co, Cu, Ni, and Ag in the multilayers. 2010-02 Thesis NonPeerReviewed application/pdf en http://eprints.utm.my/id/eprint/11369/1/NazimahKhamisSubariMFS2010.pdf Khamis @ Subari, Nazimah (2010) The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures. Masters thesis, Universiti Teknologi Malaysia, Faculty of Science.
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
language English
topic QC Physics
spellingShingle QC Physics
Khamis @ Subari, Nazimah
The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
description Giant Magnetoresistance (GMR) refers to a phenomenon of a considerable drop in electrical resistance in ultrathin ferromagnetic/non-magnetic layers structure, when a sufficiently high magnetic field is applied to the structure. Since the first time it was observed in late 1980’s, this area of research has attracted a very strong interest due to the deep fundamental physics and its promising technological potential especially in data storage industry. This dissertation discusses the magnetoresistance of ferromagnetic/non-magnetic multilayers fabricated using electron beam evaporation technique. The magnetoresistance value is studied towards the effect of compositional variance, a range of post deposited annealing temperature, and multilayer thickness in terms of number of repetition of the bilayer as well as the non-magnetic layer thicknesses. The results on compositional variance show as deposited Co/Cu/Ni gives the largest magnetoresistance value of 8.75% followed by Ni/Cu/Ni (5.85%), Co/Ag/Co (2.64%) and Ni/Ag/Ni (1.48%). These four ferromagnetic multilayers were given heat treatment with a range of elevating temperature. The temperature ranges between 200°C to 350°C, resulting the magnetoresistance of the above structures increases to 14.25%, 10.68%, 7.45% and 4.38% respectively. However, the thermal stability for each multilayer systems were degraded after further annealing at a temperature called the blocking temperature. From the investigation, it was found that the blocking temperatures (or the optimum annealing temperature) for Co/Cu/Ni, Ni/Cu/Ni, Co/Ag/Co and Ni/Ag/Ni were 280°C, 290°C, 310°C and 280°C respectively. The study of thickness dependence GMR, focus only on Co/Cu/Co structures. It was shown that in [Co/Cu/Co]n structures, the magnetoresistance increase as n increases from 1 to 20. Meanwhile, for Cox/Cuy/Cox structures, the magnetoresistance increases as y decreases from 15 nm to 1 nm with x is fixed at 6 nm. The X-ray diffraction study for the optimum structures shows peaks of Co, Cu, Ni and Ag which describe the multilayers are in the crystalline form. The atomic force microscopy (AFM) image analysis for Co and Cu thin films with elevated annealing temperature reveals that the higher the annealing temperature, the larger the grain size of the multilayer. The EDX spectrum analysis confirmed the presence of Co, Cu, Ni, and Ag in the multilayers.
format Thesis
author Khamis @ Subari, Nazimah
author_facet Khamis @ Subari, Nazimah
author_sort Khamis @ Subari, Nazimah
title The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
title_short The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
title_full The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
title_fullStr The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
title_full_unstemmed The effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
title_sort effect of composition, annealing temperature and thickness on magnetoresistance of ferromagnetic multilayer structures
publishDate 2010
url http://eprints.utm.my/id/eprint/11369/1/NazimahKhamisSubariMFS2010.pdf
http://eprints.utm.my/id/eprint/11369/
_version_ 1643645662371250176
score 13.211869

Similar Items