Publicação
Oxide thin films for spintronics application growth and characterization
| Resumo: | During my PhD research I have synthesized thin films of a material known as a diluted magnetic semiconductor (DMS) using the pulsed laser deposition (PLD) technique. This material is envisioned to be of importance in the emerging field of spintronics where both the charge and the spin of the carriers can be combined to yield unique functionalities. It was envisaged that if spin polarized charge carriers can be injected into a semiconductor efficiently at practical working temperatures then some novel devices might be fabricated. Few applications include on-chip memories, ultradense non-volatile semiconductor memories, ultra-low power devices, optical emitters with polarized output and far reaching applications in quantum computations. The material of interest in this dissertation is titanium dioxide, an optoelectronic semiconductor with a wide bandgap that can be tuned to higher or lower values by appropriate doping. It is an ideal candidate for spintronics applications because Ti leads to pretty high solubility of transition metals such as Co, in TiO2. X-ray diffraction (XRD) was used for phase analysis and crystallinity studies. High quality, single phase Co-doped TiO2 thin films were synthesized on (0001) sapphire substrates. The chemical composition of the samples was evaluated by Rutherford backscattering measurements, revealing that the distribution of Ti is homogeneous on the surface and along film depth; the Co:Ti ratio was determined for most of the films investigated. The thickness and band gap energy were determined from optical transmittance measurements carried out in a UV-VIS-near IR spectrophotometer (300 1100 nm). The resistivity of the thin films was measured by the standard four-point probe method at room temperature, and the magnetization hysteresis loops were recorded with a vibrating sample magnetometer from room temperature to 10 K. The magnetization vs. temperature curve displayed is not characteristic of a typical ferromagnet but suggest an hybrid behaviour that might be due to the presence of Co nanoclusters. This behaviour was confirmed by magnetic circular dichroism spectroscopy which suggests a spin splitting of the conduction band at the energy band edge of our films. |
|---|---|
| Autores principais: | Popovici, Nicoleta, 1973- |
| Assunto: | Filmes finos Física Teses de doutoramento - 2009 |
| Ano: | 2009 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| _version_ | 1865920840147664896 |
|---|---|
| author | Popovici, Nicoleta, 1973- |
| author_facet | Popovici, Nicoleta, 1973- Popovici, Nicoleta, 1973- |
| author_role | author |
| contributor_name_str_mv | Conde, Olinda Maria Quelhas Fernandes, 1951- Repositório Científico de Acesso Aberto da ULisboa |
| country_str | PT |
| creators_json_str | [{\"Person.name\":\"Popovici, Nicoleta, 1973-\"}] |
| datacite.contributors.contributor.contributorName.fl_str_mv | Conde, Olinda Maria Quelhas Fernandes, 1951- Repositório Científico de Acesso Aberto da ULisboa |
| datacite.creators.creator.creatorName.fl_str_mv | Popovici, Nicoleta, 1973- |
| datacite.date.Accepted.fl_str_mv | 2009-01-01T00:00:00Z |
| datacite.date.available.fl_str_mv | 2010-07-27T09:00:39Z |
| datacite.date.embargoed.fl_str_mv | 2010-07-27T09:00:39Z |
| datacite.rights.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| datacite.subjects.subject.fl_str_mv | Filmes finos Física Teses de doutoramento - 2009 |
| datacite.titles.title.fl_str_mv | Oxide thin films for spintronics application growth and characterization |
| dc.contributor.none.fl_str_mv | Conde, Olinda Maria Quelhas Fernandes, 1951- Repositório Científico de Acesso Aberto da ULisboa |
| dc.creator.none.fl_str_mv | Popovici, Nicoleta, 1973- |
| dc.date.Accepted.fl_str_mv | 2009-01-01T00:00:00Z |
| dc.date.available.fl_str_mv | 2010-07-27T09:00:39Z |
| dc.date.embargoed.fl_str_mv | 2010-07-27T09:00:39Z |
| dc.format.none.fl_str_mv | application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf text/xml |
| dc.identifier.none.fl_str_mv | http://hdl.handle.net/10451/1635 |
| dc.language.none.fl_str_mv | eng |
| dc.rights.none.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| dc.subject.none.fl_str_mv | Filmes finos Física Teses de doutoramento - 2009 |
| dc.title.fl_str_mv | Oxide thin films for spintronics application growth and characterization |
| dc.type.none.fl_str_mv | http://purl.org/coar/resource_type/c_db06 |
| description | During my PhD research I have synthesized thin films of a material known as a diluted magnetic semiconductor (DMS) using the pulsed laser deposition (PLD) technique. This material is envisioned to be of importance in the emerging field of spintronics where both the charge and the spin of the carriers can be combined to yield unique functionalities. It was envisaged that if spin polarized charge carriers can be injected into a semiconductor efficiently at practical working temperatures then some novel devices might be fabricated. Few applications include on-chip memories, ultradense non-volatile semiconductor memories, ultra-low power devices, optical emitters with polarized output and far reaching applications in quantum computations. The material of interest in this dissertation is titanium dioxide, an optoelectronic semiconductor with a wide bandgap that can be tuned to higher or lower values by appropriate doping. It is an ideal candidate for spintronics applications because Ti leads to pretty high solubility of transition metals such as Co, in TiO2. X-ray diffraction (XRD) was used for phase analysis and crystallinity studies. High quality, single phase Co-doped TiO2 thin films were synthesized on (0001) sapphire substrates. The chemical composition of the samples was evaluated by Rutherford backscattering measurements, revealing that the distribution of Ti is homogeneous on the surface and along film depth; the Co:Ti ratio was determined for most of the films investigated. The thickness and band gap energy were determined from optical transmittance measurements carried out in a UV-VIS-near IR spectrophotometer (300 1100 nm). The resistivity of the thin films was measured by the standard four-point probe method at room temperature, and the magnetization hysteresis loops were recorded with a vibrating sample magnetometer from room temperature to 10 K. The magnetization vs. temperature curve displayed is not characteristic of a typical ferromagnet but suggest an hybrid behaviour that might be due to the presence of Co nanoclusters. This behaviour was confirmed by magnetic circular dichroism spectroscopy which suggests a spin splitting of the conduction band at the energy band edge of our films. |
| dirty | 0 |
| eu_rights_str_mv | openAccess |
| format | doctoralThesis |
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| id | ul_d4def9f3bf41bc89e1d4efefb93e33a6 |
| identifier.url.fl_str_mv | http://hdl.handle.net/10451/1635 |
| instacron_str | ul |
| institution | Universidade de Lisboa |
| instname_str | Universidade de Lisboa |
| language | eng |
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| organization_str_mv | urn:organizationAcronym:ul |
| person_str_mv | Popovici, Nicoleta, 1973- |
| publishDate | 2009 |
| reponame_str | Repositório da Universidade de Lisboa |
| repository_id_str | urn:repositoryAcronym:ul |
| service_str_mv | urn:repositoryAcronym:ul |
| spelling | engptDuring my PhD research I have synthesized thin films of a material known as a diluted magnetic semiconductor (DMS) using the pulsed laser deposition (PLD) technique. This material is envisioned to be of importance in the emerging field of spintronics where both the charge and the spin of the carriers can be combined to yield unique functionalities. It was envisaged that if spin polarized charge carriers can be injected into a semiconductor efficiently at practical working temperatures then some novel devices might be fabricated. Few applications include on-chip memories, ultradense non-volatile semiconductor memories, ultra-low power devices, optical emitters with polarized output and far reaching applications in quantum computations. The material of interest in this dissertation is titanium dioxide, an optoelectronic semiconductor with a wide bandgap that can be tuned to higher or lower values by appropriate doping. It is an ideal candidate for spintronics applications because Ti leads to pretty high solubility of transition metals such as Co, in TiO2. X-ray diffraction (XRD) was used for phase analysis and crystallinity studies. High quality, single phase Co-doped TiO2 thin films were synthesized on (0001) sapphire substrates. The chemical composition of the samples was evaluated by Rutherford backscattering measurements, revealing that the distribution of Ti is homogeneous on the surface and along film depth; the Co:Ti ratio was determined for most of the films investigated. The thickness and band gap energy were determined from optical transmittance measurements carried out in a UV-VIS-near IR spectrophotometer (300 1100 nm). The resistivity of the thin films was measured by the standard four-point probe method at room temperature, and the magnetization hysteresis loops were recorded with a vibrating sample magnetometer from room temperature to 10 K. The magnetization vs. temperature curve displayed is not characteristic of a typical ferromagnet but suggest an hybrid behaviour that might be due to the presence of Co nanoclusters. This behaviour was confirmed by magnetic circular dichroism spectroscopy which suggests a spin splitting of the conduction band at the energy band edge of our films.application/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdftext/xmlptOxide thin films for spintronics application growth and characterizationPopovici, Nicoleta, 1973-Conde, Olinda Maria Quelhas Fernandes, 1951-HostingInstitutionOrganizationalRepositório Científico de Acesso Aberto da ULisboae-mailmailto:repositorio@reitoria.ulisboa.ptrepositorio@reitoria.ulisboa.pt2010-07-27T09:00:39Z20092009-01-01T00:00:00ZHandlehttp://hdl.handle.net/10451/1635http://purl.org/coar/access_right/c_abf2open accessFilmes finosFísicaTeses de doutoramento - 200940389 bytes14154 bytes13365 bytes15684 bytes12452 bytes25054 bytes103909 bytes77740 bytes16259 bytes92383 bytes403001 bytes210145 bytes1271553 bytes1351597 bytes87544 bytes6142 bytesliteraturehttp://purl.org/coar/resource_type/c_db06doctoral thesishttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/8e48a8d6-d22f-4687-a185-9cb2fe68a18b/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/235d01d7-6a19-4993-a67f-2b52f3f58bb6/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/738b8de5-02fd-48bc-a7bc-0f602ba88057/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/86c93de4-f5ae-48e9-906e-fb8a1d7b5cae/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/669d02ae-1a0b-4b2f-9919-ff22ffce5baa/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/92f4f8c2-5886-429a-bbce-cc7292592ff9/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/53a71c32-b791-4aa2-b6e7-c19919e3dc69/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/4296ba49-a6e0-4cbd-a951-3af8467947b9/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/b68e0243-2b49-44d4-8640-c4ecb2ef4148/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/4bafe8ab-3e11-4c4a-b00d-21a717a4f1df/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/2613ef82-4cf4-4abf-901d-a01975ea3098/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/c2a1877d-930e-4e83-aa20-24acf9e39b0b/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/7efdb385-9f5e-494f-bba7-ed6789b0b2be/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/b3d8598d-c628-4e23-a754-392a0c8314fb/downloadhttp://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://repositorio.ulisboa.pt/bitstreams/6dc2429f-83fd-4136-88fc-f28b33c94b3e/downloadhttp://purl.org/coar/access_right/c_abf2text/xmlfulltexthttps://repositorio.ulisboa.pt/bitstreams/22c64949-5f4a-4af4-a1f3-4c5bf2d3922e/download |
| spellingShingle | Oxide thin films for spintronics application growth and characterization Oxide thin films for spintronics application growth and characterization Popovici, Nicoleta, 1973- Filmes finos Física Teses de doutoramento - 2009 Popovici, Nicoleta, 1973- Filmes finos Física Teses de doutoramento - 2009 |
| status | SINGLETON |
| subject.fl_str_mv | Filmes finos Física Teses de doutoramento - 2009 |
| title | Oxide thin films for spintronics application growth and characterization |
| title_full | Oxide thin films for spintronics application growth and characterization |
| title_fullStr | Oxide thin films for spintronics application growth and characterization Oxide thin films for spintronics application growth and characterization |
| title_full_unstemmed | Oxide thin films for spintronics application growth and characterization Oxide thin films for spintronics application growth and characterization |
| title_short | Oxide thin films for spintronics application growth and characterization |
| title_sort | Oxide thin films for spintronics application growth and characterization |
| topic | Filmes finos Física Teses de doutoramento - 2009 |
| topic_facet | Filmes finos Física Teses de doutoramento - 2009 |
| url | http://hdl.handle.net/10451/1635 |
| visible | 1 |