Imãs são corpos de materiais magnetizáveis utilizados para gerar um forte campo magnético em sua vizinhança. Essa característica faz com que sejam empregados em diversas aplicações na vida moderna, tais como motores para a indústria eletroeletrônica e automobilística, como elementos de fixação e em acoplamentos magnéticos na indústria mecânica. O mercado de ímãs permanentes movimenta atualmente cerca de US$ 5 bilhões por ano e está em plena expansão, sendo estimado um crescimento de 12% por ano até o final desta década de 90. Tal crescimento é atribuído aos \"novos materiais\" desenvolvidos a partir da década de 80 (ímãs de terras-raras) e aos novos mercados, que foram gerados pelos próprios \"novos materiais\" (Hart, 1996). Tratando-se de materiais tão ligados às facilidades da vida moderna, a pesquisa na área de imãs está intimamente ligada ao seu desenvolvimento tecnológico. Procura-se desenvolver imãs com as melhores propriedades magnéticas para as suas aplicações, investigando ao mesmo tempo os fenômenos que regem os mecanismos físicos de magnetização. / Permanent magnets composed of magnetic powders bonded with a polymer represent the fastest growing sector of the magnetic materials market since they are ideal for the fabrication of small motors. This work presents a magnetic and structural characterization of TIve eommereial bonded magnets, Reversible and irreversible components of the total magnetization as well as magnetic interactions in the five commereial magnets are also studied, the magnets are composed by ferrite and MQP-Q nanoerystelline powders and mixtures of these two powders with 80%, 60% and 40% ferrite. Magnelie interactions were analyzed by Henkel plots, gM plots and switching field distributions. In bonded magnets, since the magnetic particles are separated from each other by a binder, it is expected that interactions are mainly dipolar in Nature. There is a progressive change in the data as the fraction of MQP-Q powder is increased. The sample with 100% ferrite shows strong magnetizing interactions at low fields. Date for hybrid magnets present increasing demagnetizing interactions as the fermion of MQP-Q increases and for the 100% MQP-Q sample, the data indicate demagnetizing effects. Reversible and irreversible magnetization components were obtained by applying two methods commanly used in magnetic materials characterization, the DCD -IRM method and the reversible susceptibility method. For the 100% ferrite magnet, in which the reversible component is small, the methods lead lo similar results. The results for both methods diverge as the reversible component! Increases, which in this case occurs with the increase of the MQP-Q powder fraction. The divergence is attributed to the idealized conditions of non-inleracting particles assumed by the DCD-IRM method. Magnetic interactions and lotai magnetization components were also studied in a melt-spun nanocrystalline Nd9Fe85B5 sample. This composition is similar to that of the MQP-Q powder and the magnetic behavior of both the bonded magnetic and the nanocrystalline precursor could be compared. Micromagnetic simulations allowed the evaluation of exchange, anisotropy and magnetostatic interactions on the magnetization reversal of nanocryslalline romposlle systems. The Monte Carlo method was applied lo a linear array of 300 magnetic moments distributed in three grains, two magnetically hard with a soft grain between them.

Imãs são corpos de materiais magnetizáveis utilizados para gerar um forte campo magnético em sua vizinhança. Essa característica faz com que sejam empregados em diversas aplicações na vida moderna, tais como motores para a indústria eletroeletrônica e automobilística, como elementos de fixação e em acoplamentos magnéticos na indústria mecânica. O mercado de ímãs permanentes movimenta atualmente cerca de US$ 5 bilhões por ano e está em plena expansão, sendo estimado um crescimento de 12% por ano até o final desta década de 90. Tal crescimento é atribuído aos \"novos materiais\" desenvolvidos a partir da década de 80 (ímãs de terras-raras) e aos novos mercados, que foram gerados pelos próprios \"novos materiais\" (Hart, 1996). Tratando-se de materiais tão ligados às facilidades da vida moderna, a pesquisa na área de imãs está intimamente ligada ao seu desenvolvimento tecnológico. Procura-se desenvolver imãs com as melhores propriedades magnéticas para as suas aplicações, investigando ao mesmo tempo os fenômenos que regem os mecanismos físicos de magnetização. / Permanent magnets composed of magnetic powders bonded with a polymer represent the fastest growing sector of the magnetic materials market since they are ideal for the fabrication of small motors. This work presents a magnetic and structural characterization of TIve eommereial bonded magnets, Reversible and irreversible components of the total magnetization as well as magnetic interactions in the five commereial magnets are also studied, the magnets are composed by ferrite and MQP-Q nanoerystelline powders and mixtures of these two powders with 80%, 60% and 40% ferrite. Magnelie interactions were analyzed by Henkel plots, gM plots and switching field distributions. In bonded magnets, since the magnetic particles are separated from each other by a binder, it is expected that interactions are mainly dipolar in Nature. There is a progressive change in the data as the fraction of MQP-Q powder is increased. The sample with 100% ferrite shows strong magnetizing interactions at low fields. Date for hybrid magnets present increasing demagnetizing interactions as the fermion of MQP-Q increases and for the 100% MQP-Q sample, the data indicate demagnetizing effects. Reversible and irreversible magnetization components were obtained by applying two methods commanly used in magnetic materials characterization, the DCD -IRM method and the reversible susceptibility method. For the 100% ferrite magnet, in which the reversible component is small, the methods lead lo similar results. The results for both methods diverge as the reversible component! Increases, which in this case occurs with the increase of the MQP-Q powder fraction. The divergence is attributed to the idealized conditions of non-inleracting particles assumed by the DCD-IRM method. Magnetic interactions and lotai magnetization components were also studied in a melt-spun nanocrystalline Nd9Fe85B5 sample. This composition is similar to that of the MQP-Q powder and the magnetic behavior of both the bonded magnetic and the nanocrystalline precursor could be compared. Micromagnetic simulations allowed the evaluation of exchange, anisotropy and magnetostatic interactions on the magnetization reversal of nanocryslalline romposlle systems. The Monte Carlo method was applied lo a linear array of 300 magnetic moments distributed in three grains, two magnetically hard with a soft grain between them.

The static and dynamic properties of spin distributions within domain walls(DWs) confined by Permalloy nanowire conduits are investigated by numerical simulations and high-speed magneto-optic polarimetry. Phase boundaries and critical points associated with DW spin distributions of various topologies are accurately determined using high-performance computing resources. Field-driven mobility curves that characterize DW propagation velocities in 20 nm thick nanowires are calculated with increasing the width of nanowires. Beyond the simple one-dimensional solution, the simulations reveal the four distinct dynamic modes. Oscillations of the field-driven DW velocity in Permalloy nanowires are observed above the Walker breakdown condition using high-speed magneto-optic polarimetry. A one-dimensional analytical model and numerical simulations of DW motion and spin dynamics are used to interpret the experimental data. Velocity oscillations are shown to be much more sensitive to properties of the DW guide structure (which also affect DW mobility) than the DW spin precessional frequency, which is a local property of the material. Transverse bias field effects on field-driven DW velocity are studied experimentally and numerically. DW velocities and spin configurations are determined as functions of longitudinal drive field, transverse bias field, and nanowire width. For a nanowire that supports vortex wall structures, factor of ten enhancements of the DW velocity are observed above the critical longitudinal drive-field (that marks the onset of oscillatory DW motion) when a transverse bias field is applied. The bias-field enhancement of DW velocity is explained by numerical simulations of the spin distribution and dynamics within a propagating DW that reveal dynamic stabilization of coupled vortex structures and suppression of oscillatory motion in the nanowire conduit resulting in uniform DW motion at high speed. Current-driven and current-assisted field-driven domain wall dynamics in ferromagnetic nanowires have thermal effects resulting from Joule heating, which make difficult to separate the spin-torque effects on DW displacements. To understand the thermal effects on DW dynamics, the temperature dependence of field-driven DW velocity is explored using high-bandwidth scanning Kerr polarimetry. Walker critical fields are decreased with increasing temperature and temperature-induced dynamic mode changes are observed. The results show that Joule heating effects are playing an important role in current-driven/current-assisted field-driven DW dynamics. / text

In der vorliegenden Arbeit wurden die mikromagnetische Struktur sowie das Ummagnetisierungsverhalten epitaktisch gewachsener MnAs Filme auf dem Substrat GaAs untersucht. Im Mittelpunkt steht die mikromagnetischen Struktur von anisotrop erspannten MnAs Filmen auf GaAs(001). Die Verspannung führt zur selbstorganisierten Anordnung ferromagnetischer Streifen. Ihre Domänenstruktur wurde mittels MFM (magnetischer Kraftmikroskopie) bestimmt und mit den Resultaten der XMCDPEEM (X-ray magnetic circular dichroism photoemission electron microscopy) verglichen. Um eine vollständige Charakterisierung der mikromagnetischen Eigenschaften der Streifenstruktur zu erreichen, wurden die MFM Experimente in einem äusseren Magnetfeld durchgeführt. Die Beantwortung der zentralen Frage nach der Domänenstruktur ist mit der Entwicklung eines mikromagnetischen Simulators für dreidimensionale magnetische Strukturen auf mesoskopischer Skala gelungen. Die Stabilität der dreidimensionalen mikromagnetischen Struktur hängt von den Eigenschaften der selbstorganisierten Streifenstruktur ab, d.h. sowohl von der Filmdicke als auch vom Verhältnis ihrer Breite zur Filmdicke - und damit der Temperatur. Durch die Erkenntnis, dass eine magnetische Struktur in der Tiefe des Streifens vorhanden ist, können die verbleibenden Unterschiede in den XMCDPEEM- und MFM-Resultaten erklärt werden. Durch die Simulationsergebnisse in Kombination mit den Experimenten wird eine widerspruchsfreie Deutung der mikromagnetischen Struktur sowie deren Ummagnetisierungsverhalten ermöglicht. Zudem wird die mikromagnetische Struktur von MnAs auf GaAs(111) simuliert und damit das Verständnis der mikromagnetischen Strukturen auf alle vorhandenen Substratorientierungen vervollständigt. / In the present thesis the micromagnetic structure, as well as the magnetization reversal, of epitaxial MnAs films on GaAs substrates are studied. The investigation is focused on the micromagnetic structure of anisotropically strained MnAs films on GaAs(001). The strain originates a selforganized array of ferromagnetic stripes. The magnetic domains were investigated using MFM (magnetic force microscopy) and the results were compared with XMCDPEEM (X-ray magnetic circular dichroism photoemission electron microscopy). To completely characterize the micromagnetic properties of the stripe structure, MFM experiments were performed in the presence of an external field. To unambiguously determine the domain structure a three-dimensional micromagnetic simulator was developed capable to calculate magnetic structures with mesoscopic dimensions. The stability of the three-dimensional micromagnetic structure depends on the properties of the selforganized stripe structure, i.e., on the film thickness as well as on the ratio of the stipe width to thickness - and thus the temperature. Taking into account the magnetization distribution in-depth, the remaining differences between the XMCDPEEM and the MFM results can be explained by the disturbing effect of the MFM tip. The results of the micromagnetic simulations, in combination with the experimental results, allow for a determination of the micromagnetic structure in an applied field throughout the phase coexistence regime. Moreover, the micromagnetic structure of MnAs films on GaAs(111) is simulated and thus the understanding of the micromagnetic properties have been extended on all substrate orientations.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-03-03T15:39:30Z No. of bitstreams: 1 josehenriquesilva.pdf: 38531594 bytes, checksum: c78eae9aa6726299a310f26bfa565039 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-06T20:17:02Z (GMT) No. of bitstreams: 1 josehenriquesilva.pdf: 38531594 bytes, checksum: c78eae9aa6726299a310f26bfa565039 (MD5) / Made available in DSpace on 2017-03-06T20:17:02Z (GMT). No. of bitstreams: 1 josehenriquesilva.pdf: 38531594 bytes, checksum: c78eae9aa6726299a310f26bfa565039 (MD5) Previous issue date: 2011-11-09 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nos últimos anos, o estudo do comportamento da magnetização em nanodiscos magnéticos tem atraído à atenção de muitos pesquisadores da área de nanomagnetismo. Devido a possibilidade dos nanodiscos apresentarem um estado de magnetização em forma de vórtice com componente fora-do-plano no seu centro, estes podem ser os possíveis substitutos dos dispositivos de armazenamento magnético utilizados atualmente. Para que os nano discos possam ser utilizados para fins de armazenamento,precisa-se conhecer com detalhes o comportamento do vórtice em diversas situações. Em trabalho recente verificou-se experimentalmente que a frequência do modo girotrópico na presença de impureza é maior que a frequência caso não houvesse impureza no nanodisco e que a frequência diminui com o aumento do diâmetro. No presente trabalho estudamos o comportamento do modo girotrópico, quando colocamos a impureza numa distância, em relação ao centro do nanodisco, menor que o raio do Modo Girotrópico e também quando colocamos a impureza numa distância maior que o raio do modo girotrópico. A impureza magnética é definida a partir da constante de acoplamento J da interação de troca entre Spin-Spin. Se a constante de acoplamento J' da interação entre impureza-Spin vizinho for maior que J(J' > J), temos uma impureza repulsiva e para J' < J a impureza é atrativa. Para estudar a influência de impurezas na frequência do modo girotrópico foram feitas simulações micromagnéticas em nanodiscos magnéticos usando valores conhecidos das constantes do Permalloy-79. Foram feitas simulações em nanodiscos com diversos diâmetros (125nm, 145nm, 175nm, 195nm, 225nm e 275nm), todos com 10nm de espessura. Nossos resultados mostram que existe uma flutuação na frequência do modo girotrópico na presença de impurezas magnéticas, o que está de acordo com resultados experimentais recentes. / In recent years, to study the behavior of magnetization in magnetic nanodisks has attracted the attention of many researchers in nanomagnetism. Due to the possibility of nanodisks to present a state of magnetization with vortex-shaped component out-of-plane at its center, this can substitute the magnetic storage devices used today. For nanodisks that can be used for storage purposes, one needs to know in detail the behavior of the vortex in many situations. In a recent study, it was experimentally found that the frequency of the gyrotropic mode in the presence of impurities is greater than the frequency, if there were no impurity in nanodisks, so that the frequency decreases with increasing the diameter. In this paper we study the behavior of gyrotropic mode when we place the impurity at a distance from the center of the nanodisks, smaller than the gyrotropic radius mode and also when the impurity placed at a distance greater than the radius of the gyrotropic mode. The magnetic impurity is defined as the coupling constant J of the exchange interaction between the Spin-Spin interaction. If the coupling constant J' from the interaction between impurity-neighbor spin is greater than J (J0 > J), we have a repulsive impurity and if J' <J the impurity is attractive. To study the influence of impuritiesin the gyrotropic frequency mode, micromagnetic simulations were made in magnetic nanodisks using known values of constants of the Permalloy-79. Nanodisks simulations were made with different diameters (125nm,145nm,175nm,195nm,225nmand275nm), all of with10nm thick. Our results show that there is a fluctuation in the gyrotropic frequency mode in the presence of magnetic impurities, which is in agreement with recent experimental results.

The thesis deals with magnetic force microscopy of soft magnetic nanostructures, mainly NiFe nanowires and thin-film elements such as discs. The thesis covers almost all aspects related to this technique - i.e. from preparation of magnetic probes and magnetic nanowires, through the measurement itself to micromagnetic simulations of the investigated samples. We observed the cores of magnetic vortices, tiny objects, both with commercial and our home-coated probes. Even domain walls in nanowires 50 nm in diameter were captured with this technique. We prepared functional probes with various magnetic coatings: hard magnetic Co, CoCr and soft NiFe. Hard probes give better signal, whereas the soft ones are more suitable for the measurement of soft magnetic structures as they do not influence significantly the imaged sample. Our probes are at least comparable with the standard commercial probes. The simulations are in most cases in a good agreement with the measurement and the theory. Further, we present our preliminary results of the probe-sample interaction modelling, which can be exploited for the simulation of magnetic force microscopy image even in the case of probe induced perturbations of the sample.

Das Thema dieser Arbeit ist die Synthese von Ferromagnet-Halbleiter-Nanodraht-Strukturen in einer Kern-Hülle-Geometrie. Diese wird mittels Molekularstrahlepitaxie unter der Verwendung von GaAs und Fe3Si ausgeführt. Im Zentrum der Arbeit steht die Frage, ob sich mit derartigen Strukturen Magnetisierungen senkrecht zum Substrat realisieren lassen. Eine solche Konfiguration der Magnetisierung innerhalb bestimmter Strukturen ist wünschenswert, denn sie bildet die Grundlage einiger zukunftsweisender spintronischer Bauteilkonzepte. Aufgrund der Formanisotropie dünner Schichten ist diese Konfiguration der Magnetisierung in planaren Strukturen nur mit erheblichem Aufwand zu bewerkstelligen. Bildet sich hingegen in den Nanodraht-Hüllen eine Stabmagnetisierung aus, so führt dies direkt zur gewünschten senkrechten Magnetisierung. Im ersten Teil dieser Arbeit wird der Epitaxie-Prozess vorgestellt. Abhängig von den Wachstumsparametern können Hüllen mit glatten Seitenflachen, einer hohen Kristallordnung, ebenen Grenzflachen zum GaAs-Kern und epitaktischer Ausrichtung realisiert werden. Der zweite Teil behandelt die magnetischen Eigenschaften der Nanodrahte. Ensemble-Charakterisierungen sind hierbei in diesem Fall nicht geeignet. Einzeldraht-Messungen hingegen zeigen, dass sich in den Nanodraht-Hüllen wie erhofft eine Stabmagnetisierung ausbildet. Der dritte und letzte Teil dieser Dissertation umfasst die Einführung mehrerer zukunftsweisender Bauteilkonzepte, basierend auf den speziellen magnetischen Eigenschaften der hier vorgestellten Nanodrahte. Dazu gehören dreidimensionale Speicherarchitekturen mit bislang unerreichten Speicherkapazitäten und zirkular polarisiertes Licht emittierende Leuchtdioden für einen enorm schnellen Spininformations-Transfer zur Intrachip-Kommunikation. / The subject of the present work is the synthesis of ferromagnet-semiconductor coreshell nanowires. To realize such structures molecular beam epitaxy has been employed. For the investigation the well-suited materials systems GaAs and Fe3Si are used. Within the framework of this thesis the open question whether a magnetization in the nanowires that is perpendicular to the nanowire’s substrate can be realized is of special interest. Such a configuration of the magnetization is desirable, because some spintronic device concepts rely on magnetizations perpendicular to the substrate. In general, with the exception of very limited and highly specific materials, the shape anisotropy of thin magnetic layers causes the magnetic moments to orient along an in-plane direction and therefore, perpendicular configurations of the magnetization do not occur at equilibrium conditions. In contrast, magnetic nanowires with moments pointing along the wire axis directly provide the desired out-of plane magnetization. In the first part, the epitaxial procedure to realize the core-shell nanowires is described. Nanowires with smooth side walls, smooth interface to the GaAs core, a fairly high structural ordering and an epitaxial orientation relationship are produced. In the second part, the magnetic properties of the core-shell nanowires are analyzed. It is shown that characterizations of an ensemble of wires cannot resolve magnetic properties of the shells. Investigations on single nanowires however revealed that the magnetization in the shells is indeed as desired oriented along the wires. Several innovative device concepts based on the specific magnetic properties of these core-shell nanowires are finally introduced in the third part of this work. Within these concepts three-dimensional magnetic recording devices with unsurpassed data storage capacities and circular polarized light emitting diodes for tremendously fast spin information transfer for intrachip communication can be realized.

Abschlussdomänenstrukturen in strukturierten weichmagnetischen dünnen Schichten wurden systematisch hinsichtlich ihrer Domänenweite, Domänenmagnetisierungsrichtung, Domänenwandtypen und Wandlängen modifiziert. Somit konnte ein umfassendes Verständnis über die Beeinflussungsmöglichkeiten des dynamischen Magnetisierungsverhaltens von Abschlussdomänenkonfigurationen im GHz-Bereich erarbeitet werden. Ein bekanntes Modell zur Berechnung der akustischen Domänenresonanzfrequenz von 180° -Domänenkonfigurationen wurde unter Berücksichtigung von Abschlussdomänen und endlichen effektiven Domänenwandweiten erfolgreich erweitert. Damit ist eine präzise Vorhersage des dynamischen Verhaltens von 180° - Abschlussdomänenstrukturen möglich. Außerdem wurde aufgezeigt, dass über die Messung der ferromagnetischen Resonanz Domänenwandumwandlungen im Magnetfeld detektiert werden können. Für Strukturen mit angepasster Anisotropie wurde unabhängig von der Anisotropiestärke eine konstante akustische Resonanzfrequenz beobachtet. Dieser unerwartete Zusammenhang wird auf die kompensatorischeWirkung von Abschlussdomänenstrukturen zurückgeführt. Abschließend wird gezeigt, dass für sogenannte Bucklingdomänenstrukturen eine signifikant größere Beeinflussung der ferromagnetischen Resonanzfrequenz durch vergleichsweise kleine statische Magnetfelder erzielt werden kann, als dies bei homogen magnetisierten Strukturen und Schichten der Fall ist. Die vorgestellten Ergebnisse dieser Arbeit zeigen, dass über eine Einstellung der ferromagnetischen Domänenstruktur das dynamische Verhalten weichmagnetischer strukturierter Schichten über einen vergleichsweise breiten Frequenzbereich hinweg gezielt modifiziert werden kann.

Abschlussdomänenstrukturen in strukturierten weichmagnetischen dünnen Schichten wurden systematisch hinsichtlich ihrer Domänenweite, Domänenmagnetisierungsrichtung, Domänenwandtypen und Wandlängen modifiziert. Somit konnte ein umfassendes Verständnis über die Beeinflussungsmöglichkeiten des dynamischen Magnetisierungsverhaltens von Abschlussdomänenkonfigurationen im GHz-Bereich erarbeitet werden. Ein bekanntes Modell zur Berechnung der akustischen Domänenresonanzfrequenz von 180° -Domänenkonfigurationen wurde unter Berücksichtigung von Abschlussdomänen und endlichen effektiven Domänenwandweiten erfolgreich erweitert. Damit ist eine präzise Vorhersage des dynamischen Verhaltens von 180° - Abschlussdomänenstrukturen möglich. Außerdem wurde aufgezeigt, dass über die Messung der ferromagnetischen Resonanz Domänenwandumwandlungen im Magnetfeld detektiert werden können. Für Strukturen mit angepasster Anisotropie wurde unabhängig von der Anisotropiestärke eine konstante akustische Resonanzfrequenz beobachtet. Dieser unerwartete Zusammenhang wird auf die kompensatorischeWirkung von Abschlussdomänenstrukturen zurückgeführt. Abschließend wird gezeigt, dass für sogenannte Bucklingdomänenstrukturen eine signifikant größere Beeinflussung der ferromagnetischen Resonanzfrequenz durch vergleichsweise kleine statische Magnetfelder erzielt werden kann, als dies bei homogen magnetisierten Strukturen und Schichten der Fall ist. Die vorgestellten Ergebnisse dieser Arbeit zeigen, dass über eine Einstellung der ferromagnetischen Domänenstruktur das dynamische Verhalten weichmagnetischer strukturierter Schichten über einen vergleichsweise breiten Frequenzbereich hinweg gezielt modifiziert werden kann.:1. Einleitung 2. Grundlagen 2.1. Magnetische Energieterme 2.1.1. Austauschenergie 2.1.2. Zeeman-Energie 2.1.3. Magnetostatische Energie 2.1.4. Anisotropie 2.2. Magnetische Mikrostrukturen 2.2.1. Domänenwände 2.3. Magnetisierungsdynamik 2.3.1. Magnetodynamik gesättigter strukturierter Schichten 2.3.2. Magnetodynamik ungesättigter magnetischer Strukturen 3. Experimentelles 3.1. Magnetooptische Domänenbeobachtung 3.2. Magnetische Rasterkraftmikroskopie 3.3. Hysteresemessung 3.4. Dynamische Charakterisierung 3.4.1. Gepulste Mikrowellen-Magnetometrie 3.4.2. Messung der ferromagnetischen Resonanz mit dem Vektor-Netzwerkanalysator 3.5. Mikromagnetische Simulationen 4. Eigenschaften ausgedehnter Referenzschichten 5. Magnetisierungsdynamik modifizierter 180-Grad-Domänenstrukturen 5.1. Erzeugung magnetischer Mikrostrukturen unterschiedlicher Domänenweite 5.2. Magnetisierungsdynamik modifizierter 180°-Grad-Domänenstrukturen im Nullfeld 5.2.1. Effekt der Abschlussdomänen 5.2.2. Effekt kleiner Domänenwandweiten 5.3. Domänenresonanz im magnetischen Feld 5.3.1. Transversales Magnetfeld 5.3.2. Longitudinales Magnetfeld 6. Dynamischer Kompensationseffekt magnetischer Domänen in strukturierten Schichten 7. Magnetisierungsdynamik von Bucklingdomänenstrukturen 7.1. Statisches Magnetisierungsverhalten linsenförmiger Elemente 7.2. Magnetisierungsdynamik linsenförmiger Elemente 7.2.1. Mikromagnetische Simulation der Bucklingstruktur 7.2.2. Diskussion der Magnetisierungsdynamik der Bucklingstruktur 8. Zusammenfassung und Ausblick A. Magnetometrische Entmagnetisierungsfaktoren nach Aharoni B. Ballistische Entmagnetisierungsfaktoren nach Aharoni C. Herleitung der akustischen Domänenresonanzfrequenz im transversalen Feld