Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering

We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30 multilayer with ultrathin Fe layers and nominal thickness of the chromium spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation. The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has been detected at zero external field. The joint fit of the reflectivity curves and Mossbauer spectra of reflectivity measured near the critical angle and at the "magnetic" peak reveals that the magnetic structure of the multilayer is formed by two spirals, one in the odd and another one in the even iron layers, with the opposite signs of rotation. The double-spiral structure starts from the surface with the almost antiferromagnetic alignment of the adjacent Fe layers. The rotation of the two spirals leads to nearly ferromagnetic alignment of the two magnetic subsystems at some depth, where the sudden turn of the magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to rotate in opposite directions. The observation of this unusual double-spiral magnetic structure suggests that the unique properties of giant magneto-resistance devices can be further tailored using ultrathin magnetic layers.Comment: 9 pages, 3 figure

Supplement to the Chronology of the Estate’s Assemblies of the Duchy of Głogów (1257–1786)

The text is a supplement to the chronological presentation of the Estate’s Assemblies of the Duchy of Głogów, prepared in 1991 by the author in his monographic book on this topic. One can prove that the first traces of the Assembly, composed from the chivalry, can be found in the middle of the 13th century. The well developed system of the estate’s assemblies in the Duchy of Głogów was liquidated after the annexion of Silesia by Prussia in 1742. The king of Prussia decided to retain only one of its elements, the so called Weichbildtag, composed of circles (Kreis) of noblemen with only limited competences. The lack of archive documents from this period results in the supplement providing only one reference to Weichbildtag in Głogów in [email protected] WrocławskiAnnales Glogovienses bis z. J. 1493, [w:] Scriptores Rerum Silesiacarum, t. X, Breslau 1877.Archiwum Państwowe w Zielonej Górze, Akta miasta Szprotawy, sygn. 218.Archiwum Państwowe we Wrocławiu, Akta Miasta Wrocławia, sygn. GGG 47 (kopia).Biblioteka Kórnicka PAN, BK 00218 „Thomus Decimus Octauus Epistolarum Legationum..., cd. 3, k 246v.–247.Codex Diplomaticus Silesiae, t. VII, cz. 2, Breslau 1875, Regesten zur schlesischen Geschichte.Codex diplomaticus Brandenburgensis, wyd. A. Riedel, cz. II, t. 3, Berlin.Codex Diplomaticus Silesiae, t. IV.Lehns- und Besitzurkunden Schlesiens und seiner einzelnen Fürstenthümer im Mittelalter, wyd. C. Grünhagen, H. Markgraf, cz. II, Leipzig 1883.Lehns- und Besitzurkunden Schlesiens und seiner einzelnen Fürstenthümer im Mittelalter, cz. I, Leipzig 1881.Neues Archiv für die Geschichte Schlesiens und der Lausitz, t. II, wyd. J.G. Worbs.Registrum St. Wenceslai, Codex Diplomaticus Silesiae, t. VI, s. 177, nr I.Sommersberg F.W., Silesiacarum rerum Scriptores..., t. III, Leipzig 1730.Urkundensammlung zur Geschichte des Fürstentums Oels bis zum Aussterben der Piastischen Herzogslinie, wyd. W. Haeusler, Breslau 1883.Klapper J., Ein Großglogauer Zinsregister aus der Zeit um 1315, „Zeitschrift des Vereins für Geschichte und Alterthum Schlesiens” 1940, t. 74.Knispel S.G., Die Geschichte der Stadt Schwiebus, von ihrem Ursprunge, bis auf das Jahr 1763, Züllichau [1765].Minsberg F., Geschichte der Stadt und Festung Gross-Glogau, t. I, Glogau 1853.Moeppert A., Das Zinsregister des Fürstentums Glogau aus dem Anfang des 14. Jahrhunderts, „Zeitschrift des Vereins für Geschichte und Alterthum Schlesiens” 1941, t. 75.Ohnesorge F., Zur Quellenkunde der Geschichte von Grünberg in Schlesien, [w:] Festschrift zur Feier des fünffzigjährigen Bestehens Friedrich-Wilhelms-Realgymnasium Grünberg in Schlesien, Grünberg 1903.Ptak M., Zgromadzenia i urzędy stanowe księstwa głogowskiego od początku XIV w. do 1742 r., Acta Universitatis Wratislaviensis nr 1344, Prawo CCX, Wrocław 1991.Weingarten J.J., Fasciculi diversorum iurium..., Nürnberg 1690, Liber I, P. III.Wentzel A., Wentzel J., Das jetzt bestehende Provinzial=Recht des Herzogthums Schlesien und der Graffschft Glatz, Zweiter Theil. Lokal=Recht. Das jetzt bestehende Lokal-Recht des Herzogthums Schlesien und der Graffschft Glatz, Breslau, Ratibor und Pleß 1840.Wolff O., Geschichte der Stadt Grünberg in Niederschlesien von ihrer Entstehung bis zur Entstehung der Reformation, Grünberg 1848.Zimmermann F.A., Beiträge zur Beschreibung von Schlesien, t. X, Brieg 1791.Stylo, Das Provinzialrecht von Niederschlesien historiach=kritisch erlätert..., Breslau 1830.Schmidt H., Geschichte der Stadt Grünberg, Grünberg 1922.Zerndt G., Geschichte von der Stadt und Kreis Schwiebus, cz. II, Schwiebus 1912.245-25714224525

Theodor Koch-Grünberg (1872-1924): A “Field Ethnologist” and his Contacts with Brazilian Intellectuals

The German ethnologist Theodor Koch-Grünberg (1872-1924) became one of the world’s leading Americanists of his era after having successfully concluded two expeditions to Amazonia. Between 1903 and 1905 he studied indigenous peoples inhabiting the regions of the rivers Rio Negro, Vaupés, and Japurá in northwestern Brazil; between 1911 and 1913 he traveled through northern Brazil and Venezuela investigating local Amerindian communities. He contacted dozens of indigenous peoples, studied their mythology, material culture, and languages. Koch-Grünberg maintained a scientific correspondence with some of the best-informed anthropologists of his time, including Adolf Bastian, Franz Boas, Arnold van Gennep and Paul Rivet. He also exchanged letters with Brazilian colleagues such as João Capistrano de Abreu (1853-1927), Teodoro Sampaio (1855-1937), and Affonso d’Escragnolle Taunay (1876-1958). Through an analysis of primary sources – the correspondence held at the Theodor Koch-Grünberg Archive of the Philipps-Universität Marburg in Germany – this article aims at contributing both to the history of Brazilian social thought and the history of German ethnology by contextualizing these relations within the broader context of social exchanges. Therefore, the history of anthropology should be written in the same way as Koch-Grünberg imagined ethnology: as an international science, based on humanistic principles and grounded on social relations

Temperature-controlled interlayer exchange coupling in strong/weak ferromagnetic multilayers: a thermo-magnetic Curie-switch

We investigate a novel type of interlayer exchange coupling based on driving a strong/weak/strong ferromagnetic tri-layer through the Curie point of the weakly ferromagnetic spacer, with the exchange coupling between the strongly ferromagnetic outer layers that can be switched, on and off, or varied continuously in magnitude by controlling the temperature of the material. We use Ni-Cu alloy of varied composition as the spacer material and model the effects of proximity-induced magnetism and the interlayer exchange coupling through the spacer from first principles, taking into account not only thermal spin-disorder but also the dependence of the atomic moment of Ni on the nearest-neighbor concentration of the non-magnetic Cu. We propose and demonstrate a gradient-composition spacer, with a lower Ni-concentration at the interfaces, for greatly improved effective-exchange uniformity and significantly improved thermo-magnetic switching in the structure. The reported magnetic multilayer materials can form the base for a variety of novel magnetic devices, such as sensors, oscillators, and memory elements based on thermo-magnetic Curie-switching in the device.Comment: 15 pages, 5 figure

Volume terms for charged colloids: a grand-canonical treatment

We present a study of thermodynamic properties of suspensions of charged colloids on the basis of linear Poisson-Boltzmann theory. We calculate the effective Hamiltonian of the colloids by integrating out the ionic degrees of freedom grand-canonically. This procedure not only yields the well-known pairwise screened-Coulomb interaction between the colloids, but also additional volume terms which affect the phase behavior and the thermodynamic properties such as the osmotic pressure. These calculations are greatly facilitated by the grand-canonical character of our treatment of the ions, and allow for relatively fast computations compared to earlier studies in the canonical ensemble. Moreover, the present derivation of the volume terms are relatively simple, make a direct connection with Donnan equilibrium, yield an explicit expression for the effective screening constant, and allow for extensions to include, for instance, nonlinear effects.Comment: 16 pages, 6 figures, published in Phys.Rev.

On the Viscosity of Concentrated Suspensions of Charged Colloids

This work is concerned with the theoretical estimation of the low-shear viscosity of concentrated suspensions of charged-stabilized latex particles. Calculations are based on the assumption that particles interacting through purely repulsive potentials behave as equivalent hard-spheres (HS), and suspension viscosity may be analyzed in the framework of HS systems. In order to predict numerically the HS radius, the pair potential due to double-layer interaction, as a function of particle concentration, was investigated by using Poisson-Boltzmann theory and the cell model. Calculations explain appropriately experimental data for a wide range of particle sizes, volume fractions and salt concentrations. The problem concerning the effective surface charge of latex particles is also discussed.Fil: Berli, Claudio Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Deiber, Julio Alcides. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Quemada, Daniel. Universite Paris VII; Franci

Electrical resistance of individual defects at a topological insulator surface

Three-dimensional topological insulators host surface states with linear dispersion, which manifest as a Dirac cone. Nanoscale transport measurements provide direct access to the transport properties of the Dirac cone in real space and allow the detailed investigation of charge carrier scattering. Here, we use scanning tunnelling potentiometry to analyse the resistance of different kinds of defects at the surface of a (Bi0.53Sb0.47)2Te3 topological insulator thin film. The largest localized voltage drop we find to be located at domain boundaries in the topological insulator film, with a resistivity about four times higher than that of a step edge. Furthermore, we resolve resistivity dipoles located around nanoscale voids in the sample surface. The influence of such defects on the resistance of the topological surface state is analysed by means of a resistor network model. The effect resulting from the voids is found to be small compared to the other defects