1,036 research outputs found
Female Initiation Rites as part of Gendered Bemba Religion and Culture: Transformations in Women’s Empowerment
Since the 1930s, female initiation rites have been a topic of interest for both anthropologists and certain White Fathers like Fr Corbeil and Fr Hinfelaar. Although the rites have been examined from various viewpoints, e.g. structural-functionalist viewpoints in the first half of the 20th century (Richards, 1940, 1956), and later by symbolic anthropologists (Rasing, 1995, 2001, 2004, and Simonsen, 2000a and 2000b), they are now mainly explained in terms of unequal gender relations and sexuality (Kamlongera, 1987; Kalunde, 1992). During my ongoing research (1992–2016), I was inspired by the interpretation of these rites by Hugo Hinfelaar, who, although not the first White Father who studied and attended these rites, was the first one who interpreted them in a primarily religious way, emphasising aspects such as transcendence, religion, matrilinity, fecundity and history. Moreover, by examining cultural and religious artefacts and symbols, including those used in initiation rites, Hinfelaar encouraged inculturation (which became a Catholic Church policy after Vatican II), contributed to the study of African Traditional Religion from a gendered viewpoint, and promoted Bemba female initiation rites. This paper will examine the resilience and transformations of female initiation rites in the past century from a gendered and religious viewpoint. It will claim that, in line with Hinfelaar’s statement that Bemba women have lost their important socio-religious position due to bena ngandu rule, colonialism and Christianity, these female rites should be seen as a way for women to hold on to and exert their power in their families and in their communities while both initiation rites and equal gender relations are encouraged by the Catholic Church today
Effect of linear polarisability and local fields on surface SHG
A discrete dipole model has been developed to describe Surface Second Harmonic Generation by centrosymmetric semiconductors. The double cell method, which enables the linear reflection problem to be solved numerically for semi-infinite systems, has been extended for the nonlinear case. It is shown that a single layer of nonlinear electric dipoles at the surface and nonlocal effects allows to describe the angle of incidence dependent anisotropic SHG obtained from oxidised Si(001) wafers. The influence of the linear response, turns out to be essential to understand the anisotropic SHG-process
Observation of strong surface state effects in the nonlinear magneto-optical response of Ni(110)
Spectroscopic magnetization induced optical Second Harmonic Generation (MSHG)
measurements from a clean Ni(110) surface reveal strong resonance effects near
2.7 eV that can be attributed to the presence of an empty surface state. The
good agreement with model calculations shows the potential of MSHG to probe
spin polarized interface band structures.Comment: REVTeX/EPS figures/Authors's single Postsript file, to appear in PRL,
our new phase-sensitive detection technique is used (see PRB, 58, R16020
(1998)), for more details see http://www.sci.kun.nl/tvs/people/petukhov
Switching of chiral magnetic skyrmions by picosecond magnetic field pulses via transient topological states
Magnetic chiral skyrmions are vortex like spin structures that appear as
stable or meta-stable states in magnetic materials due to the interplay between
the symmetric and antisymmetric exchange interactions, applied magnetic field
and/or uniaxial anisotropy. Their small size and internal stability make them
prospective objects for data storage but for this, the controlled switching
between skyrmion states of opposite polarity and topological charge is
essential. Here we present a study of magnetic skyrmion switching by an applied
magnetic field pulse based on a discrete model of classical spins and atomistic
spin dynamics. We found a finite range of coupling parameters corresponding to
the coexistence of two degenerate isolated skyrmions characterized by mutually
inverted spin structures with opposite polarity and topological charge. We
demonstrate how for a wide range of material parameters a short inclined
magnetic field pulse can initiate the reliable switching between these states
at GHz rates. Detailed analysis of the switching mechanism revealed the complex
path of the system accompanied with the excitation of a chiral-achiral meron
pair and the formation of an achiral skyrmion
Generation of single skyrmions by picosecond magnetic field pulses
We numerically demonstrate an ultrafast method to create
skyrmions in a ferromagnetic sample by applying a
picosecond (effective) magnetic field pulse in the presence of
Dzyaloshinskii-Moriya interaction. For small samples the applied magnetic field
pulse could be either spatially uniform or nonuniform while for large samples a
nonuniform and localized field is more effective. We examine the phase diagram
of pulse width and amplitude for the nucleation. Our finding could ultimately
be used to design future skyrmion-based devices.Comment: 4.5 pages+Supplemental Materia
Excitation of magnetic precession in bismuth iron garnet via a polarization-independent impulsive photomagnetic effect
A polarization-independent, nonthermal optical effect on the magnetization in
bismuth iron garnet is found, in addition to the circular
polarization-dependent inverse Faraday effect and the linear
polarization-dependent photoinduced magnetic anisotropy. Its impulsive
character is demonstrated by the field dependence of the amplitude of the
resulting precession, which cannot be explained by a long-living photo or
heat-induced anisotropy.Comment: 12 pages, 3 Figure
Stable and fast semi-implicit integration of the stochastic Landau-Lifshitz equation
We propose new semi-implicit numerical methods for the integration of the
stochastic Landau-Lifshitz equation with built-in angular momentum
conservation. The performance of the proposed integrators is tested on the 1D
Heisenberg chain. For this system, our schemes show better stability properties
and allow us to use considerably larger time steps than standard explicit
methods. At the same time, these semi-implicit schemes are also of comparable
accuracy to and computationally much cheaper than the standard midpoint
implicit method. The results are of key importance for atomistic spin dynamics
simulations and the study of spin dynamics beyond the macro spin approximation.Comment: 24 pages, 5 figure
Frequency and wavenumber selective excitation of spin waves through coherent energy transfer from elastic waves
Using spin-wave tomography (SWaT), we have investigated the excitation and
the propagation dynamics of optically-excited magnetoelastic waves, i.e.
hybridized modes of spin waves and elastic waves, in a garnet film. By using
time-resolved SWaT, we reveal the excitation dynamics of magnetoelastic waves
through coherent-energy transfer between optically-excited pure-elastic waves
and spin waves via magnetoelastic coupling. This process realizes frequency and
wavenumber selective excitation of spin waves at the crossing of the dispersion
relations of spin waves and elastic waves. Finally, we demonstrate that the
excitation mechanism of the optically-excited pure-elastic waves, which are the
source of the observed magnetoelastic waves, is dissipative in nature.Comment: 5 pages, 4 figure
Nonlinear surface magneto-plasmonics in Kretschmann multilayers
The nonlinear magneto-plasmonics aims to utilize plasmonic excitations to
control the mechanisms and taylor the efficiencies of the non-linear light
frequency conversion at the nanoscale. We investigate the mechanisms of
magnetic second harmonic generation in hybrid gold-cobalt-silver multilayer
structures, which support propagating surface plasmon polaritons at both
fundamental and second harmonic frequencies. Using magneto-optical spectroscopy
in Kretschmann geometry, we show that the huge magneto-optical modulation of
the second harmonic intensity is dominated by the excitation of surface plasmon
polaritons at the second harmonic frequency, as shown by tuning the optical
wavelength over the spectral region of strong plasmonic dispersion. Our
proof-of-principle experiment highlights bright prospects of nonlinear
magneto-plasmonics and contributes to the general understanding of the
nonlinear optics of magnetic surfaces and interfaces.Comment: Main Manuscript: 5 pages, 3 figures. Supplementary Information: 10
pages, 7 figure
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