87,819 research outputs found
Large angle magnetization dynamics measured by time-resolved ferromagnetic resonance
A time-resolved ferromagnetic resonance technique was used to investigate the
magnetization dynamics of a 10 nm thin Permalloy film. The experiment consisted
of a sequence of magnetic field pulses at a repetition rate equal to the
magnetic systems resonance frequency. We compared data obtained by this
technique with conventional pulsed inductive microwave magnetometry. The
results for damping and frequency response obtained by these two different
methods coincide in the limit of a small angle excitation. However, when
applying large amplitude field pulses, the magnetization had a non-linear
response. We speculate that one possible cause of the nonlinearity is related
to self-amplification of incoherence, known as the Suhl instabilities.Comment: 23 pages, 8 figures, submitted to PR
Electromagnetic field generation in the downstream of electrostatic shocks due to electron trapping
A new magnetic field generation mechanism in electrostatic shocks is found,
which can produce fields with magnetic energy density as high as 0.01 of the
kinetic energy density of the flows on time scales . Electron trapping during the shock formation process
creates a strong temperature anisotropy in the distribution function, giving
rise to the pure Weibel instability. The generated magnetic field is
well-confined to the downstream region of the electrostatic shock. The shock
formation process is not modified and the features of the shock front
responsible for ion acceleration, which are currently probed in laser-plasma
laboratory experiments, are maintained. However, such a strong magnetic field
determines the particle trajectories downstream and has the potential to modify
the signatures of the collisionless shock
Symmetry-broken dissipative exchange flows in thin-film ferromagnets with in-plane anisotropy
Planar ferromagnetic channels have been shown to theoretically support a
long-range ordered and coherently precessing state where the balance between
local spin injection at one edge and damping along the channel establishes a
dissipative exchange flow, sometimes referred to as a spin superfluid. However,
realistic materials exhibit in-plane anisotropy, which breaks the axial
symmetry assumed in current theoretical models. Here, we study dissipative
exchange flows in a ferromagnet with in-plane anisotropy from a dispersive
hydrodynamic perspective. Through the analysis of a boundary value problem for
a damped sine-Gordon equation, dissipative exchange flows in a ferromagnetic
channel can be excited above a spin current threshold that depends on material
parameters and the length of the channel. Symmetry-broken dissipative exchange
flows display harmonic overtones that redshift the fundamental precessional
frequency and lead to a reduced spin pumping efficiency when compared to their
symmetric counterpart. Micromagnetic simulations are used to verify that the
analytical results are qualitatively accurate, even in the presence of nonlocal
dipole fields. Simulations also confirm that dissipative exchange flows can be
driven by spin transfer torque in a finite-sized region. These results
delineate the important material parameters that must be optimized for the
excitation of dissipative exchange flows in realistic systems.Comment: 20 pages, 5 figure
Using mixed methods for analysing culture : The Cultural Capital and Social Exclusion project
This paper discusses the use of material generated in a mixed method investigation into cultural tastes and practices, conducted in Britain from 2003 to 2006, which employed a survey, focus groups and household interviews. The study analysed the patterning of cultural life across a number of fields, enhancing the empirical and methodological template provided by Bourdieu’s Distinction. Here we discuss criticisms of Bourdieu emerging from subsequent studies of class, culture and taste, outline the arguments related to the use of mixed methods and present illustrative results from the analysis of these different types of data. We discuss how the combination of quantitative and qualitative methods informed our analysis of cultural life in contemporary Britain. No single method was able to shed light on all aspects of our inquiry, lending support to the view that mixing methods is the most productive strategy for the investigation of complex social phenomena
A Capacity Building for Higher Education ERASMUS+ Project: Strategic Human Resources Management for Southeast Asian Universities (HR4ASIA)
The development and optimization of Higher Education Institutions (HEIs) is becoming more and more
important. Consequently, Human Resources Management (HRM) has gained greater prominence in
the management of these institutions. Due to the complexity of academic contexts of HEIs, HRM
models need to be able to respond to new challenges. These challenges concern selection, motivation
and development of their staff. Currently, especially in Southeast Asian countries, Human Resources
approaches need to be more efficient and tailored to current labor and societal needs. In order to
support Higher Education organizational changes in Southeast Asia, a consortium of 4 institutions
from Europe (Spain, Portugal, Italy and Lithuania) and 8 from Asia (Vietnam, Cambodia, Laos and
Thailand) lead by the University of Danang (Vietnam), applied to a Capacity Building for Higher
Education project under the framework of the Erasmus+ Program. The project “Strategic Human
Resources Management for Southeast Asian Universities” (HR4Asia) approved in 2016 and co-funded
by the European Commission aims at contributing to Higher Education organizational reform in
Southeast Asia by improving HRM at the target HEIs from Cambodia, Lao PDR, Vietnam and
Thailand. Each partner has well defined tasks according to the work packages established on the
project. This research is focused on the competences that workers need to achieve to have a better
performance in the institution. It was necessary to present and deconstruct, among others, the
concepts of competence as capacity and competency as performance, to learn how to measure
competencies and to manage competency and Human Resources. Staff involved in this project will be
able to design and define the competencies model of the structures of each HEI to define the
competency model per structure (mapping of organizational competencies and a model of
competences of structures). This is one more step to achieve the following final goals: introduce in
Southeast Asian HEIs a scheme to developing and implementing innovative HRM approaches, paying
attention to transversal and additional skills, such as communication and self-learning. Tailor-made
dissemination activities addressing non-partner HEIs, Ministries of Higher Education and other
stakeholders will promote the project objectives, paving the way for its sustainability
Meson decay in the Fock-Tani Formalism
The Fock-Tani formalism is a first principle method to obtain effective
interactions from microscopic Hamiltonians. Usually this formalism was applied
to scattering, here we introduced it to calculate partial decay widths for
mesons.Comment: Presented at HADRON05 XI. "International Conference on Hadron
Spectroscopy" Rio de Janeiro, Brazil, August 21 to 26, 200
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