High performance miniaturized passives are of great importance for advanced nanoelectronic packages for several applications including efficient power delivery. Low cost thin film capacitors fabricated directly on package (and/or on-chip) are an attractive approach towards realizing such devices. This thesis aims to explore fundamental frequency dependent dielectric and insulating properties of thin film high-k dielectric constant in the perovskite and perovskite-related complex oxides. Throughout this thesis, we have successfully observed the role of structure, strain and oxygen stoichiometry on the dielectric properties of thin film complex oxides, allowing a greater understanding of processing conditions and polarization mechanisms. In the first section of the thesis, we explore novel processing methods in the conventional ferroelectric, barium strontium titanate, \(Ba_{1-x}Sr_xTiO_3 (BST)\), using ultraviolet enhanced oxidation techniques in order to achieve improvements in the dielectric properties. Using this method, we also explore the growth of BST on inexpensive non-noble metals such as Ni which presents technical challenges due to the ability to oxidize at high temperatures. We observe a significant lowering of the dielectric loss while also lowering the process temperature which allows us to maintain an intimate interface between the dielectric layer and the metal electrode. The second section of this thesis explores the novel dielectric material, Lanthanum Strontium Nickelate, \(La_{2-x}Sr_xNiO_4 (LSNO)\), which exhibits a colossal dielectric response. For the first time, we report on the colossal dielectric properties of polycrystalline and epitaxial thin film LSNO. We observe a significant polarization dependence on the microstructure due to the grain/grain boundary interaction with charged carriers. We next grew epitaxial films on various insulating oxide substrates in order to decouple the grain boundary interaction. Here we observed substrate dependent dielectric properties associated with induced strain. We also observe, due to the p-type carriers in LSNO, pn junction formation when grown epitaxially on the conducting oxide degenerate n-type Nb-doped \(SrTiO_3\). Finally we explore the growth mechanism of epitaxial LSNO as a function of high oxygen content. Due to the ability for LSNO to take in interstitial oxygen, a reoriented growth is observed at a critical thickness, thereby allowing us to vary anisotropy as a function of deposition conditions. / Engineering and Applied Sciences

June 22, 1918, Alonzo Sergent fell asleep while conducting a train that plowed into another train killing 86 passengers and injuring another 187. 17 days later, July 9, 1918, two passenger trains collided head on in what became known as The Great Train Wreck of 1918, killing 101 people and injuring 171 people. The investigations and analysis of failure in both accidents can be attributed to a single person. During this month, the single person failed to operate the company’s train properly, which lead to a colossal disaster which affected numerous lives, loss of business revenue, loss of credibility, and had a huge social impact. Similar to an analysis of a colossal train wreck, this report focuses on the complexities behind colossal business failures, analyzes the reasons for failure and the role of the CEO, and proposes recommendations that can be used to guard future businesses against colossal failure. / text

No description available.

xxv, 207 p. ; ill. (some col.) A print copy of this title is available from the UO Libraries, under the call number: SCIENCE QD172.T6 T87 2008 / A growing interest in the physics of complex systems such as in the transition-metal oxide family has exploded recently, especially in the last 20 years or so. One notable effect is the change in electrical resistivity of a system by orders of magnitude in an applied magnetic field, coined the "colossal magnetoresistance effect". In efforts to understand these types of effects, there has been an unveiling of a rich variety of phenomena in the field of strongly correlated electron physics that has come to dominate the current scientific times. Most notable is the competition of myriad types of order: magnetic, lattice, charge and orbital all self-organize to display a fascinating array of phases on a variety of length scales. Furthermore, it has become apparent that new probes are needed to grasp some of this physics that transcends current condensed matter theory, where much of the behavior of these types of systems has remained unexplored. We have developed a new technique to gain more information about the system than with conventional x-ray diffraction. By scattering highly coherent, low energy x-rays, we can measure manganite speckle: a "fingerprint' of the microscopic structure in the bulk. The coherence of the x-rays can further be used to elucidate new insight into the dynamics of these phases. We describe here a number of novel effects near the orbital order phase transition in a half-doped manganite. We observe a small fluctuating component in the scattered signal that is correlated with three effects: both a rapidly decreasing total signal and orbital domain size, as well as an abrupt onset of a broad background intensity that we attribute to the thermal production of correlated polarons. Our results suggest that the transition is characterized by a competition between a pinned orbital domain topology that remains static, and mobile domain boundaries that exhibit slow, spatiotemporal fluctuations. This study opens up a new chapter to the study of manganite physics as coherent x-ray scattering offers a new direction to understand the strange and exotic behavior demonstrated in the multifaceted manganites. / Adviser: Stephen Kevan

No description available.

Electrical conductance in the ferromagnetic insulating (FMI) phase of manganites has been experimentally investigated. The investigations were performed on single crystals of compositions La0.82Ca0.18MnO3 and Nd0.7Pb0.3MnO3. The nature of electrical conductance is determined to be Shklovskii–Efros variable range hopping (SE–VRH). Further, at high bias levels, non–linear conductance (NLC) is observed. A “hot electron” model, that quantitatively explains the bias and temperature dependence of the NLC, consistent with the SE–VRH nature of electrical conductance, is presented. The limits of validity of the model are discussed.

Pagrindiniai bėgių tipo elektromagnetinių svaidyklių technologijos uždaviniai yra susiję su daugybe fizikinių reikinių, vykstančių sviedinio kontaktų sąlyčio su bėgiais riboje. Todėl elektromagnetinių procesų, atsirandančių dėl didelių elektros srovės tankių ir slydimo greičių tyrimas yra svarbus šios srities uždavinys. Dėl magnetinės difuzijos ir greito sviedinio judėjimo, srovė koncentruojasi galinėje kontakto dalyje, kuri dėl stipraus Joule šilimo greitai susidėvi, o tai apriboja svaidyklės efektyvumą. Disertacijoje pateikiami magnetinio lauko difuzijos tyrimai bėgių tipo svaidyklėse panaudojant specialius jutiklius magnetinių laukų matavimui. Šie nauji jutikliai, pagaminti iš plonų La0,83Sr0,17MnO3 sluoksnių, pasižyminčių milžiniškos magnetovaržos (MM) reiškiniu (MM-B-skaliariniai jutikliai), buvo pritaikyti svaidyklėse, veikiančiose statiniame ir dinaminiame režime, esant dideliems elektromagnetinių triukšmų lygiams ir mechaniniams įtempiams. Darbo metu buvo nustatyta, jog šiais jutikliais galima išmatuoti stipraus magnetinio lauko impulso amplitudę, kai nėra žinoma šių laukų kryptis. Buvo ištirti nevienalyčių magnetinių laukų pasiskirstymai bėgiuose, atsirandantys dėl artumo efekto bei greičio skinefekto, sviediniui judant greičiau nei 1500m/s. Bandymai su įtvirtintu daugelio šepetėlių konstrukcijos sviediniu parodė, kad priekiniai šepetėliai, dėl nepakankamo Lorenco jėgos sukuriamo slėgio, gali pararasti elektrinį kontaktą su bėgiais. / The development of rails and armatures which ensure a sliding solid-to-solid contact during the whole projectile acceleration is a great challenge in the field of railgun technology. Multifaceted physics exists at the sliding contact interface: The current concentrates at the rear of the interface due to magnetic diffusion processes and the fast armature movement. Consequently, Joule heating leads to enhanced wear in this region. In this dissertation, magnetic diffusion in railguns is investigated by means of measuring magnetic fields with CMR-B-scalar sensors at static and dynamic experimental conditions. These novel sensors, based on La0.83Sr0.17MnO3 thin films exhibiting colossal magnetoresistance were adapted for the use at railguns. It was found that these sensors are effective tools to measure the magnitude of high pulsed magnetic fields independent of the field orientation. Magnetic field distributions influenced by proximity and velocity skin effect could be measured in the harsh railgun environment. The obtained results allowed to estimate the skin depth in the rails at the sliding interface of a fast moving armature (>1500m/s). Furthermore experiments with fixed multiple brush armatures showed that front brushes can have contact problems in case of missing contact pressure.

In this thesis, we have performed systematical study of anomalous electric and magnetic behaviors of the 3d transition metal oxides; colossal magnetoresistance (La1−xRxMnO3 where R is a divalent alkaline earth ion) and Multiferroic (Ho1-xLaxMn2O5) systems by X-ray and Neutron scattering techniques. In our study, the enhancement of the transfer temperature for La0.8Ba0.2MnO3 under strain effect from the SrTiO3 substrate could be possible due to two reasons which one is Sr diffusion from SrTiO3 substructure, and other one is the octahedral MnO6 high symmetry are increasing. We focus the intrinsic strain effect on La0.67Ca0.33MnO3 and La0.8Ba0.2MnO3 films, and findings show that due to the different ionic sizes of doped Ca or Ba ions, the strain effect acts differently in the way it deforms. The interfacial strain effect produces opposite influences on the lattice symmetry, the average Mn¡VO bond lengths, the average oxygen disorders, the coupling symmetries inside and in the vicinity of the MnO6 octahedrons, as well as producing an opposing trend in metal-insulator and magnetic transition temperatures of the strained La0.67Ca0.33MnO3 and La0.8Ba0.2MnO3 films. The strain effects on the electronic structures of La0.67Ca0.33MnO3 and La0.8Ba0.2MnO3 thin films have been studied by O K-edge x-ray absorption near edge structure (XANES) spectroscopy. For La0.67Ca0.33MnO3, the first-principles calculations reveal that the features in the XANES spectra are associated with hybridized states between O 2p and Mn minority-spin 3d t2g and eg, La 5d/Ca 3d, and Mn 4s/Ca 4p states. An analysis of these features shows that the tensile strain decreases substantially La¡VO and Ca¡VO hybridization and TC for La0.67Ca0.33MnO3. For La0.8Ba0.2MnO3, the small compressive strain enhances slightly La¡VO and Ba¡VO hybridization and TC. In this thesis, the influence of the local structure distortion on the magnetic transition in La doped HoMn2O5 Multiferroics has been investigated systematically. The orthorhombic crystal structure of Ho1−xLaxMn2O5 is maintained up to x¡Ø0.2 but decomposed into multiphase for x¡Ù0.25. By doping La ions to a concentration of 0.1¡Øx¡Ø0.2, the formation of the RMnO3 1(13) phase can be suppressed and single-phase Ho1−xLaxMn2O5 (0.1¡Øx¡Ø0.2) compounds can be formed under 1 atm flowing oxygen. For x=0.2, a ferromagnetic FM transition at 150 K is superimposed on the paramagnetic background, which implies that the compound undergoes a ferromagnetic to antiferromagnetic (AFM) transition. This unique FM to AFM transition is observed for the first time. The FM transition is attributed to the formation of magnetic clusters in a host paramagnetic matrix. The anomalous magnetic clusters phenomena observed in Ho0.8La0.2Mn2O5 can be directly attributed to the different properties between Ho and La ions, and the differences of Ho and La ions are not only in the ionic radius but also in the electron negativity. During 90~150K, X-ray scattering diffraction presented the new addition peaks indicates the new electric density distribution, and the Neutron powder scattering diffraction (NPD) refining results show that the local structure of R-O (R: La, Ho) is un-symmetry which is conflict to the La Extended X-ray absorption fine structure (EXAFS) (which shows that the local structure of La-O becomes more symmetry than H-O. Since the refining values of the NPD are an average of entire crystal, such that it cannot tell the local changes. X-ray absorption spectrum (XAS) and EXAFS, in contrarily, can provide the local information. They implies that the temperature evolutions of the coupling strength with O 2p or unoccupied density state are opposite for the Ho and La ions in our Ho0.8La0.2Mn2O5 sample. Therefore, local change of ions position and charge redistribution happens in this specific temperature range.

The development of rails and armatures which ensure a sliding solid-to-solid contact during the whole projectile acceleration is a great challenge in the field of railgun technology. Multifaceted physics exists at the sliding contact interface: The current concentrates at the rear of the interface due to magnetic diffusion processes and the fast armature movement. Consequently, Joule heating leads to enhanced wear in this region. In this dissertation, magnetic diffusion in railguns is investigated by means of measuring magnetic fields with CMR-B-scalar sensors at static and dynamic experimental conditions. These novel sensors, based on La0.83Sr0.17MnO3 thin films exhibiting colossal magnetoresistance were adapted for the use at railguns. It was found that these sensors are effective tools to measure the magnitude of high pulsed magnetic fields independent of the field orientation. Magnetic field distributions influenced by proximity and velocity skin effect could be measured in the harsh railgun environment. The obtained results allowed to estimate the skin depth in the rails at the sliding interface of a fast moving armature (>1500m/s). Furthermore experiments with fixed multiple brush armatures showed that front brushes can have contact problems in case of missing contact pressure. / Pagrindiniai bėgių tipo elektromagnetinių svaidyklių technologijos uždaviniai yra susiję su daugybe fizikinių reikinių, vykstančių sviedinio kontaktų sąlyčio su bėgiais riboje. Todėl elektromagnetinių procesų, atsirandančių dėl didelių elektros srovės tankių ir slydimo greičių tyrimas yra svarbus šios srities uždavinys. Dėl magnetinės difuzijos ir greito sviedinio judėjimo, srovė koncentruojasi galinėje kontakto dalyje, kuri dėl stipraus Joule šilimo greitai susidėvi, o tai apriboja svaidyklės efektyvumą. Disertacijoje pateikiami magnetinio lauko difuzijos tyrimai bėgių tipo svaidyklėse panaudojant specialius jutiklius magnetinių laukų matavimui. Šie nauji jutikliai, pagaminti iš plonų La0,83Sr0,17MnO3 sluoksnių, pasižyminčių milžiniškos magnetovaržos (MM) reiškiniu (MM-B-skaliariniai jutikliai), buvo pritaikyti svaidyklėse, veikiančiose statiniame ir dinaminiame režime, esant dideliems elektromagnetinių triukšmų lygiams ir mechaniniams įtempiams. Darbo metu buvo nustatyta, jog šiais jutikliais galima išmatuoti stipraus magnetinio lauko impulso amplitudę, kai nėra žinoma šių laukų kryptis. Buvo ištirti nevienalyčių magnetinių laukų pasiskirstymai bėgiuose, atsirandantys dėl artumo efekto bei greičio skinefekto, sviediniui judant greičiau nei 1500m/s. Bandymai su įtvirtintu daugelio šepetėlių konstrukcijos sviediniu parodė, kad priekiniai šepetėliai, dėl nepakankamo Lorenco jėgos sukuriamo slėgio, gali pararasti elektrinį kontaktą su bėgiais.

In the Colossal Cave area, Pima County, Arizona, massive blocks of Paleozoic sedimentary rocks have been thrust from a southerly direction over an irregular surface of Rincon Valley granite of Laramide age. The Paleozoic rocks involved in the thrusting are the Bolsa quartzite, Abrigo formation, Martin limestone, Escabrosa limestone, Horquilla limestone, and Andrada formation. The Pantano formation (Miocene ?) is also present under the thrust sheet. The thrusting is of an imbricate nature with slip-page mainly teaking place along incompetent rock units. Large folds occur in the Escabrosa limestone and Horquilla lime-stone. A siliceous breccia is associated with thrust planes in the area. The competent units of the Paleozoic sediments were fractured and brecciated along the thrust planes. Solutions dissolved part of the silica and hematite from the Bolsa quartzite and deposited it in the fractured and brecciated zones.