The Influence of Thermal Treatment on Magnetic Moments in i-Al-Pd-Mn Quasicrystals

The influence of cooling rate on thermal strains in the quasicrystalline icosahedral Al-Pd-Mn complex metallic alloy was investigated. In general, measurements of the electronic magnetization can be used as an indirect method for determining the short-scale disorder in the crystal structure as the magnetic moments at the Mn sites are highly dependent on their local environment. Excluding the contributions of thermal vacancies and second phase precipitates by proper selection of preannealing temperatures and durations, the changes in magnetization can be ascribed to the appearance or disappearance of thermal strains in the crystal structure. It was found that water-quenching increases thermal strains irrespective of previous thermal history.</p

A case of penile fracture with complete urethral disruption during sexual intercourse: a case report

Penile fracture is a rare condition. Primarily it is a rupture of the corpus cavernosum that occurs when the penis is erect. The rupture can also affect the corpus spongiosum and the urethra. We report a case of a 37 year old man who presented with acute penile pain, penile swelling and the inability to pass urine after a blunt trauma during sexual intercourse. In emergency surgery we found bilateral partial rupture of the corpus cavernosum with complete urethral and corpus spongiosum disruption. In the one year follow up the patient presented with normal erectile and voiding function. Emergency surgical repair in penile fracture can preserve erectile and voiding function

Magnetism in multiferroic Pb5Cr3F19

We report on the first observation of a magnetic transition in multiferroic Pb5Cr3F19. The system undergoes a ferroelectric transition at TC = 545 K and probably an antiferromagnetic transition around TN = 11 K. Between 50 K and TN, the system is not paramagnetic but shows the presence of correlated spin clusters, indicating a superparamagnetic or spin glass state. The observable changes of the magnetic properties ongoing through ferroelectric phase transition show a magnetoelectric coupling that may be important for new devices

Transparenz und Evaluierbarkeit des erziehungswissenschaftlichen Publikationsaufkommens. Eine anwendungsorientierte Studie

Der Beitrag stellt Ziele und erste Ergebnisse des DFG-Projekts "Innovative bibliometrische Verfahren zur kontinuierlichen Beobachtung der sozialwissenschaftlichen Forschungsproduktion" vor. Eine Analyse des Publikationsverhaltens von Erziehungswissenschaftlern zeigt die große Bedeutung des Publikationstyps Sammelwerksbeitrag und der Publikationssprache Deutsch, aber auch eine ausgeprägte Heterogenität in der Publikationspraxis von erziehungswissenschaftlichen Institutionen. Skizziert wird schließlich der Vorschlag für einen neuen, dieser Publikationspraxis angemessenen, bibliometrischen Indikator. (DIPF/Autor

Mechanochemical Synthesis of Nanocrystalline Multiferroics Based on Bismuth Manganite

Multiferroic materials simultaneously possess two or more ferroic orders, and enable a coupling interaction between them. Multiferroic bismuth manganite is known as a material that exhibits both ferromagnetic and ferroelectric properties making it interesting for various technological applications. Unfortunately, preparation of BiMnO3 is not possible by conventional solid state reaction and BiMnO3 has been synthesized from the mixture of oxides only at high pressures (>40 kbar). The aim of this work was to synthesize BiMnO3 (BMO) without additional heating or application of high pressures. Nanocrystalline single-phased BMnO3 was prepared for the first time by mechanochemical synthesis directly from the highly activated constituent oxides, Bi2O3 and Mn2O3, in a planetary ball mill. The obtained materials were characterized by X-ray diffraction, SEM with EDS analysis, HRTEM and magnetization measurements. All the samples were found to be tetragonal perovskite with P4mm crystallographic group. The broad maxima reflections of BMO samples can be ascribed to an amorphous/disordered phase. HRTEM micrographs give clear evidence of core-shell structure with amorphous shell around the nanocrystalline BMO particles. The magnetic hysteresis behavior is similar to that of a soft ferromagnet. The magnetic properties of the obtained BMO powders were found to change as a function of milling time in a manner consistent with the variation in the nanocomposite microstructure

Magnetoelectric Coupling Springing Up in Molecular Ferroelectric: [N(C2H5)3CH3][FeCl4]

A molecule-based ferroelectric triethylmethylammonium tetrachloroferrate(III) ([N(C2H5)3CH3][FeCl4]) powder was designed as a multifunctional material exhibiting excellent multiple bistability. Prepared by the slow evaporation method at room temperature, the compound crystallizes in the non- centrosymmetric assembly of hexagonal symmetry (P63mc space group) which undergoes a reversible temperature- triggered phase transition pinpointed at 363 K to the centrosymmetric packing within the P63/mmc space group. Aside from the inseparable role of the symmetry-breaking process smoothly unveiled from the X-ray powder diffraction data, a striking change in the dielectric permittivity observed during the paraelectric-to- ferroelectric phase transition directly discloses the bistable dielectric behavior—an exceptionally high increase in the dielectric permittivity of about 360% at 100 kHz across the heating and cooling cycles is direct proof showing the highly desirable stimuli- responsive electric ordering in this improper ferroelectric architecture. Due to the magnetically modulated physical properties resulting in the coupling of magnetic and electric orderings, the flexible assembly of [N(C2H5)3CH3] [FeCl4] could be used to boost the design and development of novel magnetoelectric device

Water in the Alluaudite Type-Compounds: Synthesis, Crystal Structure and Magnetic Properties of Co₃(AsO₄)_0.5+x(HAsO₄)_2−x(H₂AsO₄)_0.5+x[(H,□)_0.5(H₂O,H₃O)_0.5]^2x+

In this study, a new cobalt arsenate belonging to the alluaudite supergroup compounds with the general formula of Co3(AsO4)0.5+x(HAsO4)2−x(H2AsO4)0.5+x[(H,□)0.5(H2O,H3O)0.5]2x+ (denoted as CoAsAllu) was synthesized under hydrothermal conditions. Its crystal structure was determined by a room-temperature single-crystal X-ray diffraction analysis: space group C2/c, a = 11.6978(8), b = 12.5713(7), c = 6.7705(5) Å, β = 113.255(5)°, V = 914.76(11) Å3, Z = 2 for As6H8Co6O25. It represents a new member of alluaudite-like protonated arsenates and the first alluaudite-like phase showing both protonation of the tetrahedral site and presence of the H2O molecules in the channels. In the asymmetric unit of CoAsAllu, one of the two Co, one of the two As and one of the seven O atoms lie at 4e special positions (site symmetry 2). The crystal structure consists of the infinite edge-shared CoO6 octahedra chains, running parallel to the [101¯] direction. The curved chains are interconnected by [(As1O4)0.5(H2As1O4)0.5]2− and [HAs2O4]2− tetrahedra forming a heteropolyhedral 3D open framework with two types of parallel channels. Both channels run along the c-axis and are located at the positions (1/2, 0, z) and (0, 0, z), respectively. The H2 and H4 hydrogen atoms of O2H2 and O4H4 hydroxyl groups are situated in channel 1, while the uncoordinated water molecule H2O7 at half-occupied 4e special positions and hydrogen atoms of O6H6 hydroxyl group were found in channel 2. The results of the magnetic investigations confirm the quasi one-dimensional structure of divalent cobalt ions. They are antiferromagnetically coupled with the intrachain interaction parameter of J ≈ −8 cm−1 and interchain parameter of J’ ≈ −2 cm−1 that become effective below the Néel temperature of 3.4 K

Water in the Alluaudite Type-Compounds: Synthesis, Crystal Structure and Magnetic Properties of Co3(AsO4)0.5+x(HAsO4)2&minus;x(H2AsO4)0.5+x[(H,&#9633;)0.5(H2O,H3O)0.5]2x+

In this study, a new cobalt arsenate belonging to the alluaudite supergroup compounds with the general formula of Co3(AsO4)0.5+x(HAsO4)2&minus;x(H2AsO4)0.5+x[(H,&#9633;)0.5(H2O,H3O)0.5]2x+ (denoted as CoAsAllu) was synthesized under hydrothermal conditions. Its crystal structure was determined by a room-temperature single-crystal X-ray diffraction analysis: space group C2/c, a = 11.6978(8), b = 12.5713(7), c = 6.7705(5) &Aring;, &beta; = 113.255(5)&deg;, V = 914.76(11) &Aring;3, Z = 2 for As6H8Co6O25. It represents a new member of alluaudite-like protonated arsenates and the first alluaudite-like phase showing both protonation of the tetrahedral site and presence of the H2O molecules in the channels. In the asymmetric unit of CoAsAllu, one of the two Co, one of the two As and one of the seven O atoms lie at 4e special positions (site symmetry 2). The crystal structure consists of the infinite edge-shared CoO6 octahedra chains, running parallel to the [101&macr;] direction. The curved chains are interconnected by [(As1O4)0.5(H2As1O4)0.5]2&minus; and [HAs2O4]2&minus; tetrahedra forming a heteropolyhedral 3D open framework with two types of parallel channels. Both channels run along the c-axis and are located at the positions (1/2, 0, z) and (0, 0, z), respectively. The H2 and H4 hydrogen atoms of O2H2 and O4H4 hydroxyl groups are situated in channel 1, while the uncoordinated water molecule H2O7 at half-occupied 4e special positions and hydrogen atoms of O6H6 hydroxyl group were found in channel 2. The results of the magnetic investigations confirm the quasi one-dimensional structure of divalent cobalt ions. They are antiferromagnetically coupled with the intrachain interaction parameter of J &asymp; &minus;8 cm&minus;1 and interchain parameter of J&rsquo; &asymp; &minus;2 cm&minus;1 that become effective below the N&eacute;el temperature of 3.4 K