Cotunneling and non-equilibrium magnetization in magnetic molecular monolayers

Transport and non-equilibrium magnetization in monolayers of magnetic molecules subject to a bias voltage are considered. We apply a master-equation approach going beyond the sequential-tunneling approximation to study the Coulomb-blockade regime. While the current is very small in this case, the magnetization shows changes of the order of the saturation magnetization for small variations of the bias voltage. Inelastic cotunneling processes manifest themselves as differential-conductance steps, which are accompanied by much larger changes in the magnetization. In addition, the magnetization in the Coulomb-blockade regime exhibits strong signatures of sequential tunneling processes de-exciting molecular states populated by inelastic cotunneling. We also consider the case of a single molecule, finding that cotunneling processes lead to the occurrence of magnetic sidebands below the Coulomb-blockade threshold. In the context of molecular electronics, we study how additional spin relaxation suppresses the fine structure in transport and magnetization.Comment: 8 pages, 8 figures, version as publishe

an International Comparison

We use data from the European Household Finance and Consumption Survey in order to examine the distributional effect of intergenerational wealth transfers on the net worth distribution in 8 European countries and compare it to recent findings for the US. To do so, we resort to the decomposition of the coefficient of variation as suggested and applied by Wolff (1987, 2002, 2015) and Wolff and Gittleman (2014). The results hint that inheritances and gifts have a vastly equalizing effect on inequality in household wealth in all 8 countries

Quantum Tunneling of Magnetization in Single Molecular Magnets Coupled to Ferromagnetic Reservoirs

The role of spin polarized reservoirs in quantum tunneling of magnetization and relaxation processes in a single molecular magnet (SMM) is investigated theoretically. The SMM is exchange-coupled to the reservoirs and also subjected to a magnetic field varying in time, which enables the quantum tunneling of magnetization (QTM). The spin relaxation times are calculated from the Fermi golden rule. The exchange interaction with tunneling electrons is shown to affect the spin reversal due to QTM. Furthermore, it is shown that the switching is associated with transfer of a certain charge between the leads.Comment: 5 pages, 3 EPS figures, final version as publishe

Four-terminal magneto-transport in graphene p-n junctions created by spatially selective doping

In this paper we describe a graphene p-n junction created by chemical doping. We find that chemical doping does not reduce mobility in contrast to top-gating. The preparation technique has been developed from systematic studies about influences on the initial doping of freshly prepared graphene. We investigated the removal of adsorbates by vacuum treatment, annealing and compensation doping using NH3. Hysteretic behavior is observed in the electric field effect due to dipolar adsorbates like water and NH3. Finally we demonstrate spatially selective doping of graphene using patterned PMMA. 4-terminal transport measurements of the p-n devices reveal edge channel mixing in the quantum hall regime. Quantized resistances of h/e^2, h/3e^2 and h/15e^2 can be observed as expected from theory.Comment: 18 pages, 5 figure

Doping dependence of the Neel temperature in Mott-Hubbard antiferromagnets: Effect of vortices

The rapid destruction of long-range antiferromagnetic order upon doping of Mott-Hubbard antiferromagnetic insulators is studied within a generalized Berezinskii-Kosterlitz-Thouless renormalization group theory in accordance with recent calculations suggesting that holes dress with vortices. We calculate the doping-dependent Neel temperature in good agreement with experiments for high-Tc cuprates. Interestingly, the critical doping where long-range order vanishes at zero temperature is predicted to be xc ~ 0.02, independently of any energy scales of the system.Comment: 4 pages with 3 figures included, minor revisions, to be published in PR

Ecology, distribution, harvest, and conservation of the Amazonian manatee, Trichechus inunguis, in Ecuador

Recientes sumarios de la distribución de los manaties amazónicos Trichechus inunguis registran especimenes de la mayor parte de la cuenca amazónica en Brasil, el oriente de Peru, y el suroriente de Colombia, pero no de Ecuador. Durante octubre y noviembre de 1983 nosotros fuimos en busca de manaties en los sistemas de los rios Aguarico y Cuyabeno de la Provincia del Napo, Ecuador oriental. Aqui documentamos la existencia de manaties amazónicos en Ecuador, proveemos estimaciones aproximadas de su actual distribución, describimos varios aspectos de su ecologia en Ecuador, documentamos el uso de manaties por gentes indigenas, y documentamos la cosecha comercial actual de manaties para carne. Manaties feuron observados por nosotros en varias localidades separadas en las tierras bajas del Ecuador oriental. Adicionalmente, reportamos varias observaciones por otros, asi como tambien registros históricos publicados que fueron previamente pasados por alto. Nuestras observaciones de manaties son de habitaciones en aguas negras en selva iluviosa primaria no alterada de tierras bajas, en aguas con un pH de 5.5 a 6.0 y temperatura de 25.0 a 30.7C. En la región del alto Cuyabeno, los indios de la tribu Siona, quienes han cosechado manaties por generaciones, se han impuesto asi mismos prohibiciones en la caza de manaties en Ecuador y tierras adyacentes de Peru. La mayoria de la carne obtenida es usada por los militares ya sea ecuatorianos o peruanos. Nosotros encontramos abundantes manaties sólo en una localidad, la Laguna Lagarto Cocha. Sin embargo, esta población esta siendo activamente cazada, y la carne es vendida a los destacamentos militares del lugar. Estimamos que si el nivel actual de caza continua al mismo ritmo los manaties amazónicos habran desaparecido del Ecuador en unos 10 a 15 anios.Recent summaries of the distribution of the Amazonian manatee Trichechus inunguis record specimens from much of the Central Amazon Basin in Brazil, eastern Peru, and extreme southeastern Colombia, but not Ecuador. During October and November of 1983 we searched for manatees in the Río Aguarico and Río Cuyabeno systems of Napo Province, eastern Ecuador. Herein we document the existence of Amazonian manatees in Ecuador, provide rough estimates of their current distribution, describe several aspects of their ecology in Ecuador, document use of manatees by indigenous peoples, and document the current commercial harvest of manatees for meat. Manatees were observed by us at several separate localities in the Amazonian lowlands of eastern Ecuador. Additionally, we report several observations by others as well as a published historical record previously overlooked. Our observations of manatees are from blackwater habitats in undisturbed, primary, lowland rainforest in water with a pH of 5.5 to 6.0 and temperature of 25.0 to 30.7C. In the upper Cuyabeno region, the Siona Indians, who have harvested manatees for generations, have a self-imposed ban on manatee hunting to protect the few remaining animals in their waters. Settlers, the military, and a commercial meat hunter continue to actively harvest Amazonian manatees in Ecuador and adjacent Peru. Much of the meat obtained is used by either the Ecuadorian or Peruvian military. We found manatees abundant at only one locality, Laguna Lagarto Cocha. However, this population is being actively hunted, and the meat sold to the local military outposts. We estimate that if the current level of harvest continues unabated, Amazonian manatees will be gone from Ecuador within 10–15 years

Adaptação metodológica de citogenética pra minhocas.

O objetivo do presente trabalho foi testar diferentes técnicas citogenéticas em minhocas da espécie Eisenia andrei Bouché, no intuito de estabelecer uma diretriz para novos estudos que proporcionem a obtenção de material com maior número de metáfases com menos custo e tempo de desenvolvimento

Manejo da água em pomares de pessegueiro.

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Avaliação nutricional e sensorial de barrinhas de cereais contendo suspensão de nanofibrilas de celulose de casca de pinhão.

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