255 research outputs found
Magnetic Behavior of Co/Pt and TbCo Nanocaps Assembly for Bit Pattern Media
Large area patterning of self-assembled alumina nanobumps, with hexagonally close-packed order, has
been used to create ordered array of bit pattern magnetic media. We have studied the magnetic properties
of perpendicular magnetic TbCo alloy and Co/Pt multilayers deposited on self assembled alumina
nanobumps. Measurement of reversal field as a function of field intensity, as well as magnetic force
microscopy images confirm the weakness of exchange coupling between bits in the case of Co/Pt multilayer
while stronger coupling is observed in the case of TbCo alloys.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3535
Magnetic Behavior of Co/Pt and TbCo Nanocaps Assembly for Bit Pattern Media
Large area patterning of self-assembled alumina nanobumps, with hexagonally close-packed order, has
been used to create ordered array of bit pattern magnetic media. We have studied the magnetic properties
of perpendicular magnetic TbCo alloy and Co/Pt multilayers deposited on self assembled alumina
nanobumps. Measurement of reversal field as a function of field intensity, as well as magnetic force
microscopy images confirm the weakness of exchange coupling between bits in the case of Co/Pt multilayer
while stronger coupling is observed in the case of TbCo alloys.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3535
Distance Properties of Short LDPC Codes and their Impact on the BP, ML and Near-ML Decoding Performance
Parameters of LDPC codes, such as minimum distance, stopping distance,
stopping redundancy, girth of the Tanner graph, and their influence on the
frame error rate performance of the BP, ML and near-ML decoding over a BEC and
an AWGN channel are studied. Both random and structured LDPC codes are
considered. In particular, the BP decoding is applied to the code parity-check
matrices with an increasing number of redundant rows, and the convergence of
the performance to that of the ML decoding is analyzed. A comparison of the
simulated BP, ML, and near-ML performance with the improved theoretical bounds
on the error probability based on the exact weight spectrum coefficients and
the exact stopping size spectrum coefficients is presented. It is observed that
decoding performance very close to the ML decoding performance can be achieved
with a relatively small number of redundant rows for some codes, for both the
BEC and the AWGN channels
Size distribution of magnetic charge domains in thermally activated but out-of-equilibrium artificial spin ice
International audienceA crystal of emerging magnetic charges is expected in the phase diagram of the dipolar kagome spin ice. An observation of charge crystallites in thermally demagnetized artificial spin ice arrays has been recently reported by S. Zhang and coworkers and explained through the thermodynamics of the system as it approaches a charge-ordered state. Following a similar approach, we have generated a partial order of magnetic charges in an artificial kagome spin ice lattice made out of ferrimagnetic material having a Curie temperature of 475 K. A statistical study of the size of the charge domains reveals an unconventional sawtooth distribution. This distribution is in disagreement with the predictions of the thermodynamic model and is shown to be a signature of the kinetic process governing the remagnetization
Large and robust electrical spin injection into GaAs at zero magnetic field using an ultrathin CoFeB/MgO injector
We demonstrate a large electrical spin injection into GaAs at zero magnetic
field thanks to an ultrathin perpendicularly magnetized CoFeB contact of a few
atomic planes (1.2 nm). The spin-polarization of electrons injected into GaAs
was examined by the circular polarization of electroluminescence from a Spin
Light Emitting Diode with embedded InGaAs/GaAs quantum wells. The
electroluminescence polarization as a function of the magnetic field closely
traces the out-of-plane magnetization of the CoFeB/MgO injector. A circular
polarization degree of the emitted light as large as 20% at 25 K is achieved at
zero magnetic field. Moreover the electroluminescence circular polarization is
still about 8% at room temperature.Comment: *Corresponding author: [email protected]
Contamination Control and Assay Results for the Majorana Demonstrator Ultra Clean Components
The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment
utilizing enriched Ge-76 detectors in 2 separate modules inside of a common
solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has
utilized world leading assay sensitivities to develop clean materials and
processes for producing ultra-pure copper and plastic components. This
experiment is now operating, and initial data provide new insights into the
success of cleaning and processing. Post production copper assays after the
completion of Module 1 showed an increase in U and Th contamination in finished
parts compared to starting bulk material. A revised cleaning method and
additional round of surface contamination studies prior to Module 2
construction have provided evidence that more rigorous process control can
reduce surface contamination. This article describes the assay results and
discuss further studies to take advantage of assay capabilities for the purpose
of maintaining ultra clean fabrication and process design.Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul
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