170 research outputs found
Conductance through a Magnetic Domain Wall in Double Exchange System
The conductance through a magnetic domain wall is calculated for the double
exchange system as a function of energy and the width of the domain wall. It is
shown that when the carrier density is low enough, the blockade is almost
complete even for the smoothly varying spin configuration, i.e., large width of
the domain wall. This result is applied to the manganese oxides.Comment: 3 pages, LaTex, 1 Postscript figur
PEMBELAJARAN TARI UNTUK PENYANDANG DOWN SYNDROME DI GIGI ART OF DANCE
ABSTRAK
Koordinasi gerak tubuh menjadi elemen yang penting dalam tari. Bagi penyandang down syndrome, tari memiliki peran dan fungsi yang serupa. Saat ini, penyandang down syndrome memiliki kesulitan menemukan ruang untuk bisa terlibat dalam proses kreatif. Dari banyaknya sanggar, hanya beberapa yang membuka kelas tari untuk penyandang down syndrome, salah satunya adalah Gigi Art of Dance Jakarta. Penelitian ini dilakukan guna hasil yang didapat untuk mendeskripsikan bagaimana perencanaan pembelajaran, proses pembelajaran, serta hasil pembelajaran tari untuk penyandang down syndrome di Gigi Art of Dance. Dalam penelitian ini metode yang digunakan adalah metode deskriptif kualitatif, sedangkan teknik pengumpulan data dengan cara observasi, wawancara dan dokumentasi.
Hasil penelitian yang didapat dalam penelitian ini bahwa dalam proses pembelajaran tari untuk penyandang down syndrome pelatih harus melakukan pengulangan gerak dalam waktu yang cukup lama sampai peserta didik bisa memahami dan menghapal gerakannya. Dalam menyampaikan satu bentuk gerak, pelatih menggunakan nama yang mudah diingat, ini bertujuan agar peserta didik bisa lebih mudah menyerap materi yang diberikan. Materi yang diberikan pun tidak hanya memberikan satu jenis tarian, melainkan dipadukan dengan jenis gerakan yang lain. Dalam menentukan materi atau bahan ajar, pelatih melakukan riset terlebih dahulu terhadap peserta didik, untuk mengetahui apa saja hal yang menarik perhatian dari masing-masing peserta didik, sehingga materi yang dipilih cocok untuk disampaikan kepada peserta didik.
Kata Kunci : Pembelajaran Tari, Down Syndrome, Peniruan, Imajinasi
ABSTRAC
Coordination of gestures is an important element in dance. For people with Down syndrome, dance has a similar role and function. Currently, people with Down syndrome have difficulty to find space to be involved in the creative process. Of the many studios, only a few have opened dance classes for people with Down syndrome, one of them is Gigi Art of Dance Jakarta. This research was conducted to describe how the learning planning, learning process, and what result from dance learning for people with Down Syndrome in Gigi Art of Dance. In this research the method is descriptive qualitative, and the data collection techniques are by observation, interview and documentation.
The results is, in the process of dance learning for people with Down Syndrome, coach must do repetition of movement for a long time until students can understand and memorize the movements. To demonstrate a movement, coach uses a easy call to every movement, aims to make students more easily to understand the material. The material did not only provide one type of dance, but was combined with other types of movements. In choose the material or teaching material, first thing to do is do some research to students, to find out what things attract the attention of each student, so the chosen material is suitable for delivery to students
Keyword : Dance learning, Down Syndrome, Imitation, imaginatio
Magneto and ferroelectric phase transitions in HoMn2O5 monocrystals
From the physical point of view multiferroics present an extremely
interesting class of systems and problems. These are essentially of two kinds.
One is what are the microscopic conditions, and sometimes constrains, which
determine the possibility to combine in one system both magnetic and
ferroelectric properties. This turned out to be a quite nontrivial question,
and usually, in conventional systems, these two phenomena tend to exclude one
another. Why it is the case is an important and still not completely resolved
issue. In the present article we report our results from magnetic properties
measurements on HoMn2O5 with short discussion about it possible origin
Anisotropic strains and magnetoresistance of La_{0.7}Ca_{0.3}MnO_{3}
Thin films of perovskite manganite La_{0.7}Ca_{0.3}MnO_{3} were grown
epitaxially on SrTiO_3(100), MgO(100) and LaAlO_3(100) substrates by the pulsed
laser deposition method. Microscopic structures of these thin film samples as
well as a bulk sample were fully determined by x-ray diffraction measurements.
The unit cells of the three films have different shapes, i.e., contracted
tetragonal, cubic, and elongated tetragonal for SrTiO_3, MgO, and LaAlO_3
cases, respectively, while the unit cell of the bulk is cubic. It is found that
the samples with cubic unit cell show smaller peak magnetoresistance than the
noncubic ones do. The present result demonstrates that the magnetoresistance of
La_{0.7}Ca_{0.3}MnO_{3} can be controlled by lattice distortion via externally
imposed strains.Comment: Revtex, 10 pages, 2 figure
Large negative magnetoresistance in thiospinel CuCrZrS4
We report on large negative magnetoresistance observed in ferromagnetic
thiospinel compound CuCrZrS. Electrical resistivity increased with
decreasing temperature according to the form proportional to
, derived from variable range hopping with strong
electron-electron interaction. Resistivity under magnetic fields was expressed
by the same form with the characteristic temperature T0 decreasing with
increasing magnetic field. Magnetoresistance ratio is
1.5 at 100 K for H=90 kOe and increases divergently with decreasing temperature
reaching 80 at 16 K. Results of magnetization measurements are also presented.
Possible mechanism of the large magnetoresistance is discussed.Comment: 9 pages, 5 figures, to be published in Solid State Commu
Self Injection length in La0.7 Ca0.3 Mno3-YBa 2Cu3O7-d ferromagnet- superconductor multi layer thin films
We have carried out extensive studies on the self-injection problem in
barrierless heterojunctions between La0.7Ca0.3MnO3 (LCMO) and YBa2Cu3O7-d
(YBCO). The heterojunctions were grown in situ by sequentially growing LCMO and
YBCO films on LaAlO3 (LAO) substrate using a pulsed laser deposition
(PLD) system. YBCO micro-bridges with 64 microns width were patterned both on
the LAO (control) and LCMO side of the substrate. Critical current, Ic, was
measured at 77K on both the control side as well as the LCMO side for different
YBCO film thickness. It was observed that while the control side showed a Jc of
~2 x 10E6 A/ cm2 the LCMO side showed about half the value for the same
thickness (1800 A). The difference in Jc indicates that a certain thickness of
YBCO has become 'effectively' normal due to self-injection. From the
measurement of Jc at two different thickness' (1800 A and 1500 A) of YBCO both
on the LAO as well as the LCMO side, the value of self-injection length (at
77K) was estimated to be ~900 A self-injection length has been quantified. A
control experiment carried out with LaNiO3 deposited by PLD on YBCO did not
show any evidence of self-injection.Comment: 6 pages, one figure in .ps forma
Optical Spectra in the Ferromagnetic States near the Charge Ordering
The optical conductivity is studied numerically for the ferromagnetic
metallic state close to the charge ordering observed in perovskite manganites.Comment: 11 pages, Latex, 6 ps figure
Spin Excitation Spectrum of LaMnO
As an effective model to describe perovskite-type manganates (La,)MnO,
the double-exchange model on a cubic lattice is investigated. Spin excitation
spectrum of the model in the ground state is studied using the spin wave
approximation. Spin wave dispersion relation observed in the inelastic neutron
scattering experiment of LaPbMnO is reproduced. Effective
values for the electron bandwidth as well as Hund's coupling is estimated from
the data.Comment: 10 pages LaTeX including 4 PS figure
Monte Carlo Simulations for the Magnetic Phase Diagram of the Double Exchange Hamiltonian
We have used Monte Carlo simulation techniques to obtain the magnetic phase
diagram of the double exchange Hamiltonian. We have found that the Berry's
phase of the hopping amplitude has a negligible effect in the value of the
magnetic critical temperature. To avoid finite size problems in our simulations
we have also developed an approximated expression for the double exchange
energy. This allows us to obtain the critical temperature for the ferromagnetic
to paramagnetic transition more accurately. In our calculations we do not
observe any strange behavior in the kinetic energy, chemical potential or
electron density of states near the magnetic critical temperature. Therefore,
we conclude that other effects, not included in the double exchange
Hamiltonian, are needed to understand the metal-insulator transition which
occurs in the manganites.Comment: 6 pages Revtex, 8 PS figure
The Density of States of hole-doped Manganites: A Scanning Tunneling Microscopy/Spectroscopy study
Variable temperature scanning tunneling microscopy/spectroscopy studies on
single crystals and epitaxial thin films of hole-doped manganites, which show
colossal magnetoresistance, have been done. We have investigated the variation
of the density of states, at and near the Fermi energy (), as a function
of temperature. Simple calculations have been carried out, to find out the
effect of temperature on the tunneling spectra and extract the variation of
density of states with temperature, from the observed data. We also report
here, atomic resolution images, on the single crystals and larger range images
showing the growth patterns on thin films. Our investigation shows
unambiguously that there is a rapid variation in density of states for
temperatures near the Curie temperature (). While for temperatures below
, a finite DOS is observed at , for temperatures near a hard
gap opens up in the density of states near . For temperatures much higher
than , this gap most likely gives way to a soft gap. The observed hard gap
for temperatures near , is somewhat higher than the transport gap for all
the materials. For different materials, we find that the magnitude of the hard
gap decreases as the of the material increases and eventually, for
materials with a close to 400 K, the value of the gap approaches zero.Comment: 9 pages RevTeX, 12 postscript figures, 1 table included in text,
submitted to Physical Review
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