The Battle of Shiloh,1911.

This book is a detailed account of the Battle of Shiloh, written by Joseph W. Rich with an introduction by Benjamin F. Shambaugh. Eleven Iowa Regiments took part in this Civil War engagement that took place on April 6-7, 1862 in Tennessee. Iowa had more men in the conflict, in proportion to is population than any other state.

Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties

Leaching of nitrate (NO3-) can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3- leaching is the anion exchange capacity (AEC), whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3- leaching. Samples from the subsurface layer (20-40 cm) of 24 representative soils of São Paulo State were characterized for particle-size distribution and for chemical and electrochemical properties. The subsoil content of adsorbed NO3- was calculated from the difference between the NO3- contents extracted with 1 mol L-1 KCl and with water; furthermore, NO3- leaching was studied in miscible displacement experiments. The results of both adsorption and leaching experiments were consistent with the well-known role exerted by AEC on the nitrate behavior in weathered soils. Multiple regression analysis indicated that in subsoils with (i) low values of remaining phosphorus (Prem), (ii) low soil pH values measured in water (pH H2O), and (iii) high pH values measured in 1 moL L-1 KCl (pH KCl), the amounts of surface positive charges tend to be greater. For this reason, NO3- leaching tends to be slower in these subsoils, even under saturated flow condition.

Second Report on the Public Archives,1907

This is a second report, submitted by Benjamin F. Shaughbum, on the Public Archives for the time period of September 18, 1906 to May 11, 1907. As a "program for immediate action" six recommendations were submitted to the Trustees of the State Library and Historical Department of Iowa under the date of September 18, 1906.

Défendre la démocratie directe : sur quelques arguments antidémocratiques des élites suisses

Plus que jamais, l'actualité mondiale ou nationale met en question le pouvoir du peuple. Là il se révolte avec fracas. Ici on le voit voter contre les autorités en place. Pour les uns il reconquiert sa liberté. Pour les autres il est aveugle et crée le désordre. Voici donc un livre sur le pouvoir. Dans la tradition de Benjamin Constant ou d'Alexis de Tocqueville, Antoine Chollet confère du souffle à l'examen des fondamentaux. Comment comprendre et articuler la liberté, l'égalité, la responsabilité, l'opposition entre une élite dite éclairée et les masses. En Suisse, quels sont les atouts exceptionnels, les dérives ou les illusions de la démocratie directe? Mal comprise elle est souvent confondue avec les libertés communales du Moyen Age. Ou admise avec des réserves suspectes. L'auteur en appelle à plus de rigueur et, fort de ses convictions, conclut par des appréciations sévères sur la politique suisse. Il décèle dans ses élites des tendances clairement antidémocratiques. Et inversement, il expose les raisons d'une confiance renforcée en l'institution même de la démocratie directe.

Enhanced electron-electron correlations in nanometric epitaxial SrRuO3 epitaxial films

Epitaxial and fully strained SrRuO3 thin films have been grown on SrTiO3(100). At initial stages the growth mode is three-dimensional- (3D-)like, leading to a finger-shaped structure aligned with the substrate steps and that eventually evolves into a 2D step-flow growth. We study the impact that the defect structure associated with this unique growth mode transition has on the electronic properties of the films. Detailed analysis of the transport properties of nanometric films reveals that microstructural disorder promotes a shortening of the carrier mean free path. Remarkably enough, at low temperatures, this results in a reinforcement of quantum corrections to the conductivity as predicted by recent models of disordered, strongly correlated electronic systems. This finding may provide a simple explanation for the commonly observed¿in conducting oxides-resistivity minima at low temperature. Simultaneously, the ferromagnetic transition occurring at about 140 K, becomes broader as film thickness decreases down to nanometric range. The relevance of these results for the understanding of the electronic properties of disordered electronic systems and for the technological applications of SrRuO3¿and other ferromagnetic and metallic oxides¿is stressed.

Tunable epitaxial growth of magnetoresistive La2/3Sr1/3MnO3 thin films

We report on the growth of epitaxial La2/3Sr1/3MnO3 thin films on buffered Si(001) substrates. We show that a suitable choice of the buffer heterostructure allows one to obtain epitaxial (00h), (0hh), and (hhh) manganite thin films. The magnetotransport properties are investigated and we have found that the low-field magnetoresistance is directly related to the width of the normal-to-plane rocking curves, irrespective of the film orientation. The magnetic anisotropy of these films has also been determined.

Magnetoresistance at artificial interfaces in the itinerant SrRuO3 ferromagnet

The magnetoresistance across interfaces in the itinerant ferromagnetic oxide SrRuO3 have been studied. To define appropriately the interfaces, epitaxial thin films have been grown on bicrystalline and laser-patterned SrTiO3 substrates. Comparison is made with results obtained on similar experiments using the double-exchange ferromagnetic oxide La2/3Sr1/3MnO3. It is found that in SrRuO3, interfaces induce a substantial negative magnetoresistance, although no traces of the low-field spin tunneling magnetoresistance are found. We discuss these results on the basis of the distinct degree of spin polarization in ruthenates and manganites and the different nature of the surface magnetic layer formed at interfaces.

Magneto-optical Kerr effect in laser-patterned La2/3Sr1/3MnO3 epitaxial thin films

In this study, we have performed magneto-optical Kerr effect (MOKE) measurement on epitaxial La2/3Sr1/3MnO3 thin films containing artificial interfaces created by laser-patterning the SrTiO3 substrate. The observed increase of the resistivity and of the high-field magnetoresistance when measuring the films across the interface arrays are related to the reduction of the magnetization of the interfaces with respect to the rest of the film. As observed by the local MOKE probe, the structural disorder in the manganite film induced by the underlying patterned substrate leads to a large spin disorder responsible for a strong high-field susceptibility of the resistance.

SrRuO3/SrTiO3/SrRuO3 heterostructures for magnetic tunnel junctions

We report on the growth and characterization of SrRuO3 single layers and SrRuO3/SrTiO3/SrRuO3 heterostructures grown on SrTiO3(100) substrates. The thickness dependence of the coercivity was determined for these single layers. Heterostructures with barrier thickness tb=1, 2.5, and 4 nm were fabricated, with electrodes having thickness ranging from 10 to 100 nm. The hysteresis loops of heterostructures with tb=2.5¿nm, 4 nm reveal uncoupled magnetic switching of the electrodes. Therefore, these heterostructures can be used for the fabrication of magnetic tunneling junctions.

Self-interference of charge carriers in ferromagnetic SrRuO3

We report a systematic study of the low-temperature electrical conductivity in a series of SrRuO3 epitaxial thin films. At relatively high temperature the films display the conventional metallic behavior. However, a well-defined resistivity minimum appears at low temperature. This temperature dependence can be well described in a weak localization scenario: the resistivity minimum arising from the competition of electronic self-interference effects and the normal metallic character. By appropriate selection of the film growth conditions, we have been able to modify the mean-free path of itinerant carriers and thus to tune the relative strength of the quantum effects. We show that data can be quantitatively described by available theoretical models.

Kerr measurements on single-domain SrRuO3 thin films

We report on the magneto-optical measurements of an epitaxial SrRuO3 film grown on SrTiO3 (0 0 1), which previously was determined to be single domain orientated by x-ray diffraction and Raman spectroscopy techniques. Our experiments reveal a large Kerr rotation, which reaches a maximum value of about 0.5° at low temperature. By measuring magnetic hysteresis loops at different temperatures, we determined the temperature dependence of the Kerr rotation in the polar configuration. Values of the anisotropic magnetoresistance ~ 20% have been measured. These values are remarkably higher than those of other metallic oxides such as manganites. This striking difference can be attributed to the strong spin-orbit interaction of the Ru 4d ion in the SrRuO3 compound.