Magnon spin Hall magnetoresistance of a gapped quantum paramagnet

Motivated by recent experimental work, we consider spin transport between a normal metal and a gapped quantum paramagnet. We model the latter as the magnonic Mott-insulating phase of an easy-plane ferromagnetic insulator. We evaluate the spin current mediated by the interface exchange coupling between the ferromagnet and the adjacent normal metal. For the strongly interacting magnons that we consider, this spin current gives rise to a spin Hall magnetoresistance that strongly depends on the magnitude of the magnetic field, rather than its direction. This Letter may motivate electrical detection of the phases of quantum magnets and the incorporation of such materials into spintronic devices.Comment: 5 pages, 5 figure

The effect of confinement on the deformation of microfluidic drops

We study the deformation of drops squeezed between the floor and ceiling of a microchannel and subjected to a hyperbolic flow. We observe that the maximum deformation of drops depends on both the drop size and the rate of strain of the external flow and can be described with power laws with exponents 2.59 +/- 0.28 and 0.91 +/- 0.05 respectively. We develop a theoretical model to describe the deformation of squeezed drops based on the Darcy approximation for shallow geometries and the use of complex potentials. The model describes the steady-state deformation of the drops as a function of a non-dimensional parameter Ca d^2, where Ca is the capillary number (proportional to the strain rate and the drop size) and d is a confinement parameter equal to the drop size divided by the channel height. For small deformations, the theoretical model predicts a linear relationship between the deformation of drops and this parameter, in good agreement with the experimental observations.Comment: 6 pages, 7 figure

Magnon-Mediated Indirect Exciton Condensation through Antiferromagnetic Insulators

Electrons and holes residing on the opposing sides of an insulating barrier and experiencing an attractive Coulomb interaction can spontaneously form a coherent state known as an indirect exciton condensate. We study a trilayer system where the barrier is an antiferromagnetic insulator. The electrons and holes here additionally interact via interfacial coupling to the antiferromagnetic magnons. We show that by employing magnetically uncompensated interfaces, we can design the magnon-mediated interaction to be attractive or repulsive by varying the thickness of the antiferromagnetic insulator by a single atomic layer. We derive an analytical expression for the critical temperature $T_c$ of the indirect exciton condensation. Within our model, anisotropy is found to be crucial for achieving a finite $T_c$, which increases with the strength of the exchange interaction in the antiferromagnetic bulk. For realistic material parameters, we estimate $T_c$ to be around 7 K, the same order of magnitude as the current experimentally achievable exciton condensation where the attraction is solely due to the Coulomb interaction. The magnon-mediated interaction is expected to cooperate with the Coulomb interaction for condensation of indirect excitons, thereby providing a means to significantly increase the exciton condensation temperature range.Comment: 7+13 Pages, 2+1 figures. Added discussion of retardation effects. Accepted for publication in Phys. Rev. Let

Agricultural productivity in the United States: catching-up and the business cycle

This paper examines the relation between the business cycle and convergence in levels of total factor productivity (TFP) across states. First, we find evidence of convergence in TFP levels across the different phases of the business cycle, but the speed of convergence was much greater during periods of contraction in economic activity than during periods of expansion. Second, we find that technology embodied in capital was an important source of productivity growth in agriculture. As with the rate of catch-up, the embodiment effect was much stronger during low economic activity phases of the business cycle.Agriculture, Convergence, Total factor productivity

Regional business cycle phases in Spain

© 2019 The Authors.This document is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the published version of a published work that appeared in final form in Studies of Applied Economics.We characterize regional business cycles for Spain using monthly Social Security affiliations. Based on a set of Markov-switching models, we find substantial synchronization of regional business cycles, which has increased since the Great Recession. We do however evidence a regional leading and lagging performance that repeats itself across the different recessions. Typically, earlier signals of national recessions appear in the Islands and Valencia, and are propagated from the periphery to the center. Moreover, north-western regions tend to start the regional recoveries with a significant lag

Nonlocal Spin Transport as a Probe of Viscous Magnon Fluids

Magnons in ferromagnets behave as a viscous fluid over a length scale, the momentum-relaxation length, below which momentum-conserving scattering processes dominate. We show theoretically that in this hydrodynamic regime viscous effects lead to a sign change in the magnon chemical potential, which can be detected as a sign change in the nonlocal resistance measured in spin transport experiments. This sign change is observable when the injector-detector distance becomes comparable to the momentum-relaxation length. Taking into account momentum- and spin-relaxation processes, we consider the quasiconservation laws for momentum and spin in a magnon fluid. The resulting equations are solved for nonlocal spin transport devices in which spin is injected and detected via metallic leads. Because of the finite viscosity we also find a backflow of magnons close to the injector lead. Our work shows that nonlocal magnon spin transport devices are an attractive platform to develop and study magnon-fluid dynamics

Agricultural productivity in the United States: catching-up and the business cycle

This paper examines the relation between the business cycle and convergence in levels of total factor productivity (TFP) across states. First, we find evidence of convergence in TFP levels across the different phases of the business cycle, but the speed of convergence was much greater during periods of contraction in economic activity than during periods of expansion. Second, we find that technology embodied in capital was an important source of productivity growth in agriculture. As with the rate of catch-up, the embodiment effect was much stronger during low economic activity phases of the business cycle

Génesis y aportación dialéctica para una nueva bioinformación cooperativizada integramente

Tesis Univ. Compplutense de Madrid, 1980.Fac. de Ciencias de la InformaciónTRUEProQuestpu

Génesis y aportación dialéctica para una nueva bioinformación cooperativizada integramente

Tesis Univ. Compplutense de Madrid, 1980.Fac. de Ciencias de la InformaciónTRUEProQuestpu

La comunicación interna y los conflictos laborales internos de la Agencia de Regulación y Control de Electricidad - ARCONEL

En la actualidad el éxito de toda empresa o institución se fundamenta en la comunicación interna ya que su propósito es llevar a cabo el cambio por ende el desarrollo empresarial. El objetivo del presente trabajo de investigación es establecer y definir parámetros que permitan mejorar las relaciones laborales en la Agencia de Control y Regulación de Electricidad ARCONEL, a fin de potencializar todos los recursos e influir sobre la acción en beneficio de la institución. Se inicia con una descripción de la Agencia, su misión, visión, objetivos estratégicos, atribuciones y estructura organizacional. Se incluye el marco conceptual considerando el clima laboral y sus dimensiones, la cultura organizacional, satisfacción laboral, conflictos laborales y su resolución, relaciones de poder. Posteriormente, se realiza un diagnóstico de la ARCONEL con la realización de entrevistas a informantes calificados y la aplicación de encuestas a los servidores, se realiza un análisis que permite identificar el manejo de la comunicación y conflictos laborales, donde encontramos varias situaciones para mejorar la comunicación interna, las relaciones personales entre sus integrantes y su ambiente laboral. Finalmente, se plantea una propuesta de plan de comunicación interna, a fin de establecer estrategias que permitan dirigir, orientar, motivar y propiciar un clima que incentive la participación del personal reduciendo a la mínima expresión los conflictos laborales. Finalmente las conclusiones y recomendaciones