subject:(Magneto resistance)

Universidade Federal do Maranhão

1. Carlos Cesar Costa. Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos.

Degree: 2008, Universidade Federal do Maranhão

URL: http://www.tedebc.ufma.br//tde_busca/arquivo.php?codArquivo=303

►

No presente trabalho de dissertação do curso de mestrado, estudamos as propriedades magnéticas de filmes nanométricos simples como: ferro sobre óxido de magnésio (Fe/MgO) e… (more)

▼

No presente trabalho de dissertação do curso de mestrado, estudamos as propriedades magnéticas de filmes nanométricos simples como: ferro sobre óxido de magnésio (Fe/MgO) e permalloy (FeNi) em temperatura ambiente, obtidos pelo processo de eltro-deposição por sputtering. Os resultados experimentais foram interpretados de acordo com os modelos fenomenológicos que levam em conta os termos mais relevantes da energia livre magnética do sistema. Fizemos uma abordagem em conformidade com a literatura sobre os principais mecanismos que originam a resistência elétrica em filmes metálicos magnéticos, tais como: resistência elétrica ôhmica, efeito Hall, magnetoresistência anisotrópica (AMR). É feita uma descrição das principais técnicas experimentais usadas na caracterização de filmes nanométricos, como o Magnetômetro de Efeito Kerr Magneto-óptico (MOKE), Ressonância Ferromagnética (FMR) e Magneto-resistência (MR). Esta última técnica, que usa o método das quatro pontas, é utilizada para obter as curvas de magneto-resistência. Neste trabalho, estudamos o efeito da magneto-resistência anisotrópica em filmes simples, onde as curvas de magnetoresistência estão associadas às competições entre as energias Zeeman e de anisotropia magnética. O efeito da AMR foi verificado para as amostras de filmes nanométricos via simulação numérica. Para o desenvolvimento da pesquisa, montamos um Dispositivo de Variação de Campo Magnético DC (DVCM DC) e os dados experimentais são obtidos via instrumentação virtual. As curvas de magneto-resistência foram interpretadas de acordo com o modelo fenomenológico e utilizamos ainda as curvas de histerese, obtidas por MOKE como parâmetros.

In the present work of dissertation of the master s degree course, we studied the magnetic properties of films simple nanometric s as: iron on oxide of magnesium (F/MgO) and permalloy (FeNi) in room temperature, obtained by the eltro-deposition process by sputtering. The experimental results were interpreted in agreement with the models phenomenological that take into account the most relevant terms of the magnetic free energy of the system. We made an approach in accordance with the literature on the main mechanisms that originate the electric resistance in magnetic metallic films, such as: resistance electric ohm s, effects hall, anisotropic magnetoresistance (AMR). it is made a description of the main experimental techniques used in the characterization of films nanometric s, as the Magnetometer Optical for Kerr Effect (MOKE), Ferromagnetic Resonance (FMR) and Magnetoresistance (MR). This last technique, that it uses the method of the four tips, it is used to obtain the magnetoresistance curves. In this work, we studied the effect of the anisotropic magnetoresistance in simple films, where the magnetoresistance curves are associated to the competitions enter the energies Zeeman and of anisotropic magnetic. The effect of AMR was verifies for the samples of films nanometric s through numeric simulation. For the development of the research, we set up a Device of…

Advisors/Committee Members: Carlos Chesman de Araújo Feitosa, Antonio Jose Silva Oliveira.

Subjects/Keywords: magneto-resistance; magnetic materials; magnetic field; magneto-resistência; FISICA; campo magnético; materiais magnéticos

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Costa, C. C. (2008). Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos. (Thesis). Universidade Federal do Maranhão. Retrieved from http://www.tedebc.ufma.br//tde_busca/arquivo.php?codArquivo=303

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Costa, Carlos Cesar. “Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos.” 2008. Thesis, Universidade Federal do Maranhão. Accessed January 24, 2021. http://www.tedebc.ufma.br//tde_busca/arquivo.php?codArquivo=303.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Costa, Carlos Cesar. “Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos.” 2008. Web. 24 Jan 2021.

Vancouver:

Costa CC. Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos. [Internet] [Thesis]. Universidade Federal do Maranhão; 2008. [cited 2021 Jan 24]. Available from: http://www.tedebc.ufma.br//tde_busca/arquivo.php?codArquivo=303.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Costa CC. Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos. [Thesis]. Universidade Federal do Maranhão; 2008. Available from: http://www.tedebc.ufma.br//tde_busca/arquivo.php?codArquivo=303

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Utah

2. Gautam, Bhoj Raj. Magnetic field effect in organic films and devices.

Degree: PhD, Physics & Astronomy, 2013, University of Utah

URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2517/rec/1502

► In this work, we focused on the magnetic field effect in organic films and devices, including organic light emitting diodes (OLEDs) and organic photovoltaic (OPV)… (more)

▼ In this work, we focused on the magnetic field effect in organic films and devices, including organic light emitting diodes (OLEDs) and organic photovoltaic (OPV) cells.We measured magnetic field effect (MFE) such as magnetoconductance (MC) and magneto-electroluminescence (MEL) in OLEDs based on several π-conjugated polymers and small molecules for fields B∼2mT. Magnetic field effect (MFE) measured on three isotopes of Poly (dioctyloxy) phenylenevinylene (DOO-PPV) showed that both regular and ultra-small effects are isotope dependent. This indicates that MFE response in OLED is mainly due to the hyperfine interaction (HFI).We also performed spectroscopy of the MFE including magneto-photoinduced absorption (MPA) and magneto-photoluminescence (MPL) at steady state conditions in several systems. This includes pristine Poly[2-methoxy-5-(2-ethylhexyl-oxy)-1,4-phenylene-vinylene] (MEH-PPV) films, MEH-PPV films subjected to prolonged illumination, and MEH-PPV/[6,6]-Phenyl C61 butyric acid methyl ester (PCBM) blend, as well as annealed and pristine C60 thin films. For comparison, we also measured MC and MEL in organic diodes based on the same materials. By directly comparing the MPA and MPL responses in films to MC and MEL in organic diodes based on the same active layers, we are able to relate the MFE in organic diodes to the spin densities of theexcitations formed in the device, regardless of whether they are formed by photon absorption or carrier injection from the electrodes.We also studied magneto-photocurrent (MPC) and power conversion efficiency (PCE) of a 'standard' Poly (3-hexylthiophene)/PCBM device at various Galvinoxyl radical wt%. We found that the MPC reduction with Galvinoxyl wt% follows the same trend as that of the PCE enhancement. In addition, we also measured the MPC response of a series of OPV cells. We attribute the observed broad MPC to short-lived charge transfer complex species, where spin mixing is caused by the difference, Δg of the donor/acceptor g factors; whereas narrow MPC is due to HFI within long-lived polaron-pairs.

Subjects/Keywords: Electroluminescence; Hyperfine; Magneto-resistance; Photocurrent; Photoinduced absorption; Polaron pair

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gautam, B. R. (2013). Magnetic field effect in organic films and devices. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2517/rec/1502

Chicago Manual of Style (16^th Edition):

Gautam, Bhoj Raj. “Magnetic field effect in organic films and devices.” 2013. Doctoral Dissertation, University of Utah. Accessed January 24, 2021. http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2517/rec/1502.

MLA Handbook (7^th Edition):

Gautam, Bhoj Raj. “Magnetic field effect in organic films and devices.” 2013. Web. 24 Jan 2021.

Vancouver:

Gautam BR. Magnetic field effect in organic films and devices. [Internet] [Doctoral dissertation]. University of Utah; 2013. [cited 2021 Jan 24]. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2517/rec/1502.

Council of Science Editors:

Gautam BR. Magnetic field effect in organic films and devices. [Doctoral Dissertation]. University of Utah; 2013. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2517/rec/1502

Victoria University of Wellington

3. Bailey, Joseph. Giant magneto resistance (GMR) sensors for non destructive testing.

Degree: 2015, Victoria University of Wellington

URL: http://hdl.handle.net/10063/9060

► The thesis investigates the use of giant magneto resistance sensors for eddy current testing in order to identify defects in steel pipes. An automated test… (more)

Subjects/Keywords: Magnetic sensors; Giant magneto resistance sensors; GMR; Engineering instruments

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bailey, J. (2015). Giant magneto resistance (GMR) sensors for non destructive testing. (Masters Thesis). Victoria University of Wellington. Retrieved from http://hdl.handle.net/10063/9060

Chicago Manual of Style (16^th Edition):

Bailey, Joseph. “Giant magneto resistance (GMR) sensors for non destructive testing.” 2015. Masters Thesis, Victoria University of Wellington. Accessed January 24, 2021. http://hdl.handle.net/10063/9060.

MLA Handbook (7^th Edition):

Bailey, Joseph. “Giant magneto resistance (GMR) sensors for non destructive testing.” 2015. Web. 24 Jan 2021.

Vancouver:

Bailey J. Giant magneto resistance (GMR) sensors for non destructive testing. [Internet] [Masters thesis]. Victoria University of Wellington; 2015. [cited 2021 Jan 24]. Available from: http://hdl.handle.net/10063/9060.

Council of Science Editors:

Bailey J. Giant magneto resistance (GMR) sensors for non destructive testing. [Masters Thesis]. Victoria University of Wellington; 2015. Available from: http://hdl.handle.net/10063/9060

University of Minnesota

4. Yunus, Mohammad. Spin polarized charge carrier injection, transport, and detection in organic semiconductors.

Degree: PhD, Electrical Engineering, 2011, University of Minnesota

URL: http://purl.umn.edu/108311

► In this thesis we explore spin polarized charge carrier injection, transport, and detection in organic semiconductors. Device structures considered have one or more ferromagnetic contacts… (more)

▼ In this thesis we explore spin polarized charge carrier injection, transport, and detection in organic semiconductors. Device structures considered have one or more ferromagnetic contacts to the organic semiconductor, and the condition for which charge carrier injection from ferromagnetic contacts is strongly spin polarized is discussed. Spin injection into semiconductors can be greatly enhanced if the injection mechanism is spin selective, such as is the case for tunnelling from ferromagnetic contacts. By contrast, if the carrier injection is by thermionic emission or another process that does not depend on spin, the injection is only weakly spin polarized. To discuss spin transport and spin detection, we consider a unipolar organic spin valve consisting of an organic semiconductor layer sandwiched between two ferromagnetic contacts. The polarizations of the magnetic contacts can be parallel or anti-parallel. Spin and charge carrier transport in the organic semiconductor is described by spin dependent transport equations in drift-diffusion approximation and the spin detection process is through magneto-resistance. We discuss the impact of various degrees of spin relaxation in organic semiconductors on the spatial variation of the spin current and its effect on magneto-resistance. The spatial profile of the spin current inside the organic semiconductor depends not only on the spin diffusion length but also on the alignment of the contact polarizations. However, the magneto-resistance decreases strongly with decreasing spin diffusion length. Electron tunnelling from a ferromagnetic contact can have significant spin dependence because the spatial part of the electron wave function is different for the majority and minority spin states of the ferromagnetic contacts. The tunnelling process occurs from the ferromagnetic contact through an insulating layer into the organic semiconductor. The insulating layer is modeled first as an ohmic layer with spin dependent contact resistances. The effectiveness of spin dependent contact resistances on spin polarized injection and magneto-resistance is examined on the basis of a simple analytical model. We then model the insulating layer as a tunnel barrier with spin dependent rate equations. Both majority and minority spin electrons of the ferromagnetic contact tunnel through the insulating layer into the localized molecular states of the organic semiconductor at the semiconductor/insulator interface. Tunnelling matrix elements and transition rates of the two spin types are calculated using a Transfer Hamiltonian approach. The transition rates are thus spin dependent and used in rate equations to calculate the injected (extracted) current for carriers of either spin direction. We explore the various aspects of the ferromagnetic contacts, the thickness and barrier height of the insulating layer, and the energy of the localized molecular states on spin injection and magneto-resistance. Consistent with the experimental data, the spin injection from ferromagnetic contacts can be…

Subjects/Keywords: Magneto-resistance; Organic semiconductors; Spin detection; Spin injection; Spin transport; Electrical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yunus, M. (2011). Spin polarized charge carrier injection, transport, and detection in organic semiconductors. (Doctoral Dissertation). University of Minnesota. Retrieved from http://purl.umn.edu/108311

Chicago Manual of Style (16^th Edition):

Yunus, Mohammad. “Spin polarized charge carrier injection, transport, and detection in organic semiconductors.” 2011. Doctoral Dissertation, University of Minnesota. Accessed January 24, 2021. http://purl.umn.edu/108311.

MLA Handbook (7^th Edition):

Yunus, Mohammad. “Spin polarized charge carrier injection, transport, and detection in organic semiconductors.” 2011. Web. 24 Jan 2021.

Vancouver:

Yunus M. Spin polarized charge carrier injection, transport, and detection in organic semiconductors. [Internet] [Doctoral dissertation]. University of Minnesota; 2011. [cited 2021 Jan 24]. Available from: http://purl.umn.edu/108311.

Council of Science Editors:

Yunus M. Spin polarized charge carrier injection, transport, and detection in organic semiconductors. [Doctoral Dissertation]. University of Minnesota; 2011. Available from: http://purl.umn.edu/108311

5. Pater, Laurent. Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites.

Degree: Docteur es, Mathématiques et applications, 2013, Rennes 1

URL: http://www.theses.fr/2013REN1S101

►

Les conducteurs composites sont constitués d'hétérogénéités microscopiques mais apparaissent comme homogènes à l'échelle macroscopique. La description de leur comportement nécessite l'homogénéisation des équations de conduction… (more)

▼

Les conducteurs composites sont constitués d'hétérogénéités microscopiques mais apparaissent comme homogènes à l'échelle macroscopique. La description de leur comportement nécessite l'homogénéisation des équations de conduction régissant chacune de leurs phases. Cette thèse s'intéresse à certaines lois effectives pour les conducteurs composites en présence d'un champ magnétique constant. Dans le premier chapitre, on rappelle quelques résultats d'électrophysique (effet Hall, magnétorésistance) et de la théorie de l'homogénéisation (H-convergence) ainsi que son extension à des problèmes à forte conductivité. Dans le chapitre deux, on étudie l'effet Hall dans des composites bidimensionnels à deux phases très contrastées et on compare le résultat d'homogénéisation à celui obtenu avec une structure fibrée renforcée. Le troisième chapitre généralise ce cas particulier et étend la loi comportementale obtenue à des matériaux cylindriques non périodiques sans hypothèse géométrique sur leur section. Les chapitres deux et trois soulignent des différences importantes entre la dimension deux et la dimension trois au niveau des problèmes de conduction à fort contraste. Un quatrième chapitre est consacré à l'étude de la magnétorésistance en dimension trois et met en avant une forte interaction entre la direction du champ magnétique et l'énergie dissipée dans le matériau complétant ainsi un résultat antérieur en dimension deux.

A composite conductor is composed of microscopic heterogeneities but appears as a homogeneous medium on the macroscopic scale. Describing the behavior of such materials requires the homogenization of the conduction equations which rule each of their phases. In this PhD thesis, we study a few effective laws for composite conductors in the presence of a constant magnetic field. In the first chapter, we recall a few results on electro-physics (Hall effect, magneto-resistance) and on the homogenization theory (H-convergence) as well as its extension to high-conductivity problems. In the second chapter, we study the Hall effect in two-dimensional high-contrast two-phase composites and we compare the result to the one obtained with a three-dimensional fibre-reinforced structure. The third chapter generalizes this particular case and extends the perturbation law to non-periodic cylindrical composites without any geometrical assumption on their cross section. The chapters two and three underline the gap between dimension two and dimension three in high-conductivity problems. The fourth chapter analyses the magneto-resistance in a three-dimensional composite medium and outlines a strong interaction between the direction of the magnetic field and the dissipated energy in the material; this completes a previous work on the two-dimensional case.

Advisors/Committee Members: Briane, Marc (thesis director).

Subjects/Keywords: Équations aux dérivées partielles; Homogénéisation; Composites; Hall, Effet; Magnétorésistance; Hall effect; Magneto-resistance; Composites; Differential equations, Partial

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Pater, L. (2013). Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites. (Doctoral Dissertation). Rennes 1. Retrieved from http://www.theses.fr/2013REN1S101

Chicago Manual of Style (16^th Edition):

Pater, Laurent. “Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites.” 2013. Doctoral Dissertation, Rennes 1. Accessed January 24, 2021. http://www.theses.fr/2013REN1S101.

MLA Handbook (7^th Edition):

Pater, Laurent. “Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites.” 2013. Web. 24 Jan 2021.

Vancouver:

Pater L. Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites. [Internet] [Doctoral dissertation]. Rennes 1; 2013. [cited 2021 Jan 24]. Available from: http://www.theses.fr/2013REN1S101.

Council of Science Editors:

Pater L. Homogénéisation de l'effet Hall et de la magnétorésistance dans des composites : Homogenization of the Hall effect and the magneto-resistance in composites. [Doctoral Dissertation]. Rennes 1; 2013. Available from: http://www.theses.fr/2013REN1S101

University of New Mexico

6. Casias, Lilian K. Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection.

Degree: Electrical and Computer Engineering, 2019, University of New Mexico

URL: https://digitalrepository.unm.edu/ece_etds/456

► In order to tackle vertical transport, lateral transport must be better understood. There are added challenges to determining the lateral bulk carrier concentration in… (more)

Subjects/Keywords: Magneto-Resistance; Multi-Carrier Analysis; Substrate Removal; Vertical transport; Lateral Transport; Infrared Detectors; Electrical and Computer Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Casias, L. K. (2019). Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection. (Doctoral Dissertation). University of New Mexico. Retrieved from https://digitalrepository.unm.edu/ece_etds/456

Chicago Manual of Style (16^th Edition):

Casias, Lilian K. “Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection.” 2019. Doctoral Dissertation, University of New Mexico. Accessed January 24, 2021. https://digitalrepository.unm.edu/ece_etds/456.

MLA Handbook (7^th Edition):

Casias, Lilian K. “Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection.” 2019. Web. 24 Jan 2021.

Vancouver:

Casias LK. Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection. [Internet] [Doctoral dissertation]. University of New Mexico; 2019. [cited 2021 Jan 24]. Available from: https://digitalrepository.unm.edu/ece_etds/456.

Council of Science Editors:

Casias LK. Transport in Mid-Wavelength Infrared (MWIR) p- and n-type InAsSb and InAs/InAsSb Type-II Strained Layer Superlattices (T2SLs) for infrared detection. [Doctoral Dissertation]. University of New Mexico; 2019. Available from: https://digitalrepository.unm.edu/ece_etds/456

Georgia State University

7. Ye, Tianyu. Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation.

Degree: PhD, Physics and Astronomy, 2015, Georgia State University

URL: https://scholarworks.gsu.edu/phy_astr_diss/75

► This dissertation summarizes three research projects related to microwave radiation induced electron transport properties in the GaAs/AlGaAs two dimensional electron systems. In chronological order,… (more)

Subjects/Keywords: Two dimensional electron system; Magneto-transport; Microwave radiation induced zero resistance states; Microwave radiation induced magneto-resistance oscillations; Microwave reflection; Microwave power dependence; Microwave linear polarization dependence; Microwave circular polarization dependence

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ye, T. (2015). Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation. (Doctoral Dissertation). Georgia State University. Retrieved from https://scholarworks.gsu.edu/phy_astr_diss/75

Chicago Manual of Style (16^th Edition):

Ye, Tianyu. “Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation.” 2015. Doctoral Dissertation, Georgia State University. Accessed January 24, 2021. https://scholarworks.gsu.edu/phy_astr_diss/75.

MLA Handbook (7^th Edition):

Ye, Tianyu. “Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation.” 2015. Web. 24 Jan 2021.

Vancouver:

Ye T. Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation. [Internet] [Doctoral dissertation]. Georgia State University; 2015. [cited 2021 Jan 24]. Available from: https://scholarworks.gsu.edu/phy_astr_diss/75.

Council of Science Editors:

Ye T. Magnetotransport and Remote Sensing of Microwave Reflection of Two Dimensional Electron Systems under Microwave Excitation. [Doctoral Dissertation]. Georgia State University; 2015. Available from: https://scholarworks.gsu.edu/phy_astr_diss/75

North Carolina State University

8. Ramahandran, Shivaraman. Zinc Oxide based Diluted Magnetic Semiconductors.

Degree: PhD, Materials Science and Engineering, 2007, North Carolina State University

URL: http://www.lib.ncsu.edu/resolver/1840.16/3015

► During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser… (more)

▼ During my graduate research I have synthesized materials known as diluted magnetic semiconductors (DMS) as epitaxial thin film structures using the process of pulsed laser deposition (PLD). These materials are envisioned to be of importance in the emerging field of spintronics where the charge as well as the spin of the charge carriers can be combined to yield unique functionalities to yield novel devices including, on-chip memories, ultra-low power devices etc. The material of interest in this dissertation was zinc oxide, a wide bandgap optoelectronic semiconductor. ZnO has a bandgap of 3.3 eV. It is an ideal candidate for spintronics applications, because Zn is the last of the first row transition metals, which leads to pretty high solubility of transition metals such as Co, Mn and V in ZnO. In a diluted magnetic semiconductor a fraction of the host atoms is substituted by the transition metal dopant ion. We have found that we can synthesize very high quality, single phase and single crystalline Zn(TM)O thin films on basal plane sapphire single crystals (-Al2O3). We have analyzed the magnetic properties of the three systems of ZnVO, ZnCoO and ZnMnO and found that ZnCoO and ZnMnO exhibit ferromagnetic ordering up to room temperature, when synthesized under high vacuum. In these conditions, the samples have a reasonable concentration of point defects which drive ZnO to n-type conductivity. By a combination of insitu and exsitu variation of parameters we have been able to tune the electronic and magnetic properties of these systems. From these studies we conclude that the main mechanism of magnetic ordering in these DMS materials is through a combination of defect related carrier induced exchange and bound magnetic polaron exchange. Device structures were fabricated using the as deposited samples to study the possibility of spin injection through semiconductors. We have observed that at low temperatures we see a considerable effect from this phenomenon in a magnetic tunnel junction kind of configuration. Hence, this study opens up new avenues and possibilities for a variety of spintronics applications. Advisors/Committee Members: Prof.Nadia.A.Elmasry, Committee Member (advisor), Prof.Jagdish Narayan, Committee Chair (advisor), Prof.John.F.Muth, Committee Member (advisor), Prof.John.T.Prater, Committee Member (advisor).

Subjects/Keywords: optoelectronics; spintronics; magneto-transport; thin films; magnetic; Diluted magnetic semiconductors; epitaxy; transmission electron microscopy; tunnel junction; magneto-resistance; spin injection

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ramahandran, S. (2007). Zinc Oxide based Diluted Magnetic Semiconductors. (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/3015

Chicago Manual of Style (16^th Edition):

Ramahandran, Shivaraman. “Zinc Oxide based Diluted Magnetic Semiconductors.” 2007. Doctoral Dissertation, North Carolina State University. Accessed January 24, 2021. http://www.lib.ncsu.edu/resolver/1840.16/3015.

MLA Handbook (7^th Edition):

Ramahandran, Shivaraman. “Zinc Oxide based Diluted Magnetic Semiconductors.” 2007. Web. 24 Jan 2021.

Vancouver:

Ramahandran S. Zinc Oxide based Diluted Magnetic Semiconductors. [Internet] [Doctoral dissertation]. North Carolina State University; 2007. [cited 2021 Jan 24]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/3015.

Council of Science Editors:

Ramahandran S. Zinc Oxide based Diluted Magnetic Semiconductors. [Doctoral Dissertation]. North Carolina State University; 2007. Available from: http://www.lib.ncsu.edu/resolver/1840.16/3015

9. Sagar, S. Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites.

Degree: Physics, 2010, Cochin University of Science and Technology

URL: http://dyuthi.cusat.ac.in/purl/2552

►

This thesis lays importance in the investigation on the multiferroic and thermooelectric properties of selected representatives of low bandwidth and intermediate band width manganites. The… (more)

Subjects/Keywords: Thermoelectric properties; Sodium Doped Lanthanum manganites; Multiferroic properties; low bandwidth manganites; intermediate band width manganites; Strontium doped Gd manganite; magneto resistance; dielectric properties

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sagar, S. (2010). Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites. (Thesis). Cochin University of Science and Technology. Retrieved from http://dyuthi.cusat.ac.in/purl/2552

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sagar, S. “Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites.” 2010. Thesis, Cochin University of Science and Technology. Accessed January 24, 2021. http://dyuthi.cusat.ac.in/purl/2552.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sagar, S. “Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites.” 2010. Web. 24 Jan 2021.

Vancouver:

Sagar S. Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites. [Internet] [Thesis]. Cochin University of Science and Technology; 2010. [cited 2021 Jan 24]. Available from: http://dyuthi.cusat.ac.in/purl/2552.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sagar S. Investigations on the Multiferroic and Thermoelectric properties of Low and Intermediate band width Manganites. [Thesis]. Cochin University of Science and Technology; 2010. Available from: http://dyuthi.cusat.ac.in/purl/2552

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of South Florida

10. Siyambalapitiya, Chamila S. Growth and physical properties of magnetite thin films.

Degree: 2006, University of South Florida

URL: https://scholarcommons.usf.edu/etd/2705

► This project focused on two aspects of magnetite thin films. The first was to find optimum parameters and conditions for deposition of stoichiometeric Magnetite films… (more)

Subjects/Keywords: PLD; Magnetite; Verwey; M-H loops; Magneto-resistance; IV; American Studies; Arts and Humanities

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Siyambalapitiya, C. S. (2006). Growth and physical properties of magnetite thin films. (Thesis). University of South Florida. Retrieved from https://scholarcommons.usf.edu/etd/2705

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Siyambalapitiya, Chamila S. “Growth and physical properties of magnetite thin films.” 2006. Thesis, University of South Florida. Accessed January 24, 2021. https://scholarcommons.usf.edu/etd/2705.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Siyambalapitiya, Chamila S. “Growth and physical properties of magnetite thin films.” 2006. Web. 24 Jan 2021.

Vancouver:

Siyambalapitiya CS. Growth and physical properties of magnetite thin films. [Internet] [Thesis]. University of South Florida; 2006. [cited 2021 Jan 24]. Available from: https://scholarcommons.usf.edu/etd/2705.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Siyambalapitiya CS. Growth and physical properties of magnetite thin films. [Thesis]. University of South Florida; 2006. Available from: https://scholarcommons.usf.edu/etd/2705

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Kentucky

11. Tyagi, Pawan. FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES.

Degree: 2008, University of Kentucky

URL: https://uknowledge.uky.edu/gradschool_diss/614

► Fabrication of molecular spin devices with ferromagnetic electrodes coupled with a high spin molecule is an important challenge. This doctoral study concentrated on realizing a… (more)

▼ Fabrication of molecular spin devices with ferromagnetic electrodes coupled with a high spin molecule is an important challenge. This doctoral study concentrated on realizing a novel molecular spin device by the bridging of magnetic molecules between two ferromagnetic metal layers of a ferromagnetic-insulator-ferromagnetic tunnel junction on its exposed pattern edges. At the exposed sides, distance between the two metal electrodes is equal to the insulator film thickness; insulator film thickness can be precisely controlled to match the length of a target molecule. Photolithography and thin-film deposition were utilized to produce a series of tunnel junctions based on molecular electrodes of multilayer edge molecular electrodes (MEME) for the first time. In order to make a microscopic tunnel junction with low leakage current to observe the effect of ~10,000 molecules bridged on the exposed edge of a MEME tunnel barrier, growth conditions were optimized; stability of a ~2nm alumina insulator depended on its ability to withstand process-induced mechanical stresses. The conduction mechanism was primarily 1) tunneling from metal electrode to oranometalic core by tunneling through alkane tether that acts as a tunnel barrier 2) rapid electron transfer within the oranometalic Ni-CN-Fe cube and 3) tunneling through alkane tether to the other electrode. Well defined spin-states in the oranometalic Ni-CN-Fe cube would determine electron spin-conduction and possibly provide a mechanism for coupling. MEME with Co/NiFe/AlOx/NiFe configurations exhibited dramatic changes in the transport and magnetic properties after the bridging of oranometalic molecular clusters with S=6 spin state. The molecular cluster produced a strong antiferromagnetic coupling between two ferromagnetic electrodes to the extent, with a lower bound of 20 erg/cm,2 that properties of individual magnetic layers changed significantly at RT. Magnetization, ferromagnetic resonance and magnetic force microscopy studies were performed. Transport studies of this configuration of MEME exhibited molecule-induced current suppression by ~6 orders by blocking both molecular channels and tunneling between metal leads in the planar 25μm2 tunnel junction area. A variety of control experiments were performed to validate the current suppression observation, especially critical due to observed corrosion in electrochemical functionalization step. The spin devices were found to be sensitive to light radiation, temperature and magnetic fields. Along with the study of molecular spin devices, several interesting ideas such as ~9% energy efficient ultrathin TaOx based photocell, simplified version of MEME fabrication, and chemical switching were realized. This doctoral study heralds a novel molecular spin device fabrication scheme; these molecular electrodes allow the reliable study of molecular components in molecular transport.

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Tyagi, P. (2008). FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES. (Doctoral Dissertation). University of Kentucky. Retrieved from https://uknowledge.uky.edu/gradschool_diss/614

Chicago Manual of Style (16^th Edition):

Tyagi, Pawan. “FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES.” 2008. Doctoral Dissertation, University of Kentucky. Accessed January 24, 2021. https://uknowledge.uky.edu/gradschool_diss/614.

MLA Handbook (7^th Edition):

Tyagi, Pawan. “FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES.” 2008. Web. 24 Jan 2021.

Vancouver:

Tyagi P. FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES. [Internet] [Doctoral dissertation]. University of Kentucky; 2008. [cited 2021 Jan 24]. Available from: https://uknowledge.uky.edu/gradschool_diss/614.

Council of Science Editors:

Tyagi P. FABRICATION AND CHARACTERIZATION OF MOLECULAR SPINTRONICS DEVICES. [Doctoral Dissertation]. University of Kentucky; 2008. Available from: https://uknowledge.uky.edu/gradschool_diss/614

Université Paris-Sud – Paris XI

12. Zorni, Chiara. Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling.

Degree: Docteur es, Physique, 2012, Université Paris-Sud – Paris XI

URL: http://www.theses.fr/2012PA112031

►

La problématique étudiée est le contrôle non destructif par courants de Foucault de matériaux ferromagnétiques à l’aide d’un capteur à magnétorésistance géante (GMR). Durant ces… (more)

▼

La problématique étudiée est le contrôle non destructif par courants de Foucault de matériaux ferromagnétiques à l’aide d’un capteur à magnétorésistance géante (GMR). Durant ces travaux deux aspects complémentaires ont été abordés : l’un concerne la mesure expérimentale pour essayer de quantifier et de s’affranchir du bruit de structure et du champ magnétique rémanent, l’autre le développement d’un modèle numérique d’interaction. En ce qui concerne la partie expérimentale plusieurs études avec un capteur GMR qui présente un intérêt particulier en raison de sa bonne sensibilité à basses fréquences, de sa dynamique et de la relative simplicité de mise en œuvre ont été conduites et ont permis d’identifier et quantifier les phénomènes d’artefacts spécifiques aux matériaux ferromagnétiques : le bruit de structure et le champ magnétique rémanent. Une solution basée sur une combinaison linéaire des données expérimentales obtenues à plusieurs fréquences est appliquée pour atténuer le bruit dû à la structure du matériau. Le champ magnétique rémanent a été analysé expérimentalement et un circuit d’asservissement permettant de fixer un point de polarisation dans la zone de fonctionnement linéaire de la GMR et ainsi d’atténuer les perturbations dues aux champs magnétiques rémanents est mis en place. En parallèle et dans l’optique de développer des outils de simulation permettant de mieux comprendre les phénomènes physiques et ainsi d’optimiser les procédés de contrôle, un modèle numérique d’interaction simulant le cas du contrôle d’une pièce plane ferromagnétique d’une ou plusieurs couches pouvant contenir un ou plusieurs défauts est développé. Il étend un modèle déjà existant dans un cas non-ferromagnétique déjà intégré dans la plateforme de simulation CIVA développé par le CEA-LIST et permettant la simulation du Contrôle Non Destructif par Courants de Foucault. Il est basé sur une méthode d’intégrales de volume (VIM) et l’utilisation des tenseurs ou dyades de Green. La solution est obtenue après la discrétisation du volume de calcul et l’application d’une variante de Galerkin de la Méthode des Moments (MoM). La réponse de la sonde est ensuite calculée en appliquant le théorème de réciprocité de Lorentz. Des collaborations avec deux laboratoires universitaires (le Laboratoire de Génie Électrique de Paris (LGEP) et l’Université de Cassino (Italie)) ont permis de comparer les résultats issus des trois différents modèles sur un cas de la littérature. Les résultats se sont révélés satisfaisants et plusieurs études de convergence ont permis d’analyser la stabilité du modèle.

The aim of this work is the eddy-current testing (ECT) of ferromagnetic materials within magnetic sensors, such as Giant Magneto-Resistances (GMR). Two complementary aspects have been studied. Experimental measurements have been carried out in order to quantify and minimize the noise coming from the materials structure and residual magnetization. On the other hand, a model has been developed in order to be able to simulate the electromagnetic interactions…

Advisors/Committee Members: Lambert, Marc (thesis director).

Subjects/Keywords: Contrôle non destructif; Courants de Foucault; Matériau ferromagnétique; Équation intégrale; Dyade de Green; Capteur à magnétorésistance géante; Champ magnétique rémanent; Asservissement d’une bobine de polarisation; Cyde d’hystérésis magnétique; Combinaisons de fréquences; Non destructive testing; Eddy current; Ferromagnetic materials; Integral equation; Dyadic’s Green function; Giant magneto resistance sensor; Residual magnetization; Polarization monitoring coil; Magnetic hysteresis; Frequencies combination

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zorni, C. (2012). Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling. (Doctoral Dissertation). Université Paris-Sud – Paris XI. Retrieved from http://www.theses.fr/2012PA112031

Chicago Manual of Style (16^th Edition):

Zorni, Chiara. “Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling.” 2012. Doctoral Dissertation, Université Paris-Sud – Paris XI. Accessed January 24, 2021. http://www.theses.fr/2012PA112031.

MLA Handbook (7^th Edition):

Zorni, Chiara. “Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling.” 2012. Web. 24 Jan 2021.

Vancouver:

Zorni C. Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling. [Internet] [Doctoral dissertation]. Université Paris-Sud – Paris XI; 2012. [cited 2021 Jan 24]. Available from: http://www.theses.fr/2012PA112031.

Council of Science Editors:

Zorni C. Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction : Eddy current non destructive testing of ferromagnetic materials : experimentation and modeling. [Doctoral Dissertation]. Université Paris-Sud – Paris XI; 2012. Available from: http://www.theses.fr/2012PA112031

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations