14,283 research outputs found
Joint Channel-and-Data Estimation for Large-MIMO Systems with Low-Precision ADCs
The use of low precision (e.g., 1-3 bits) analog-to-digital convenors (ADCs)
in very large multiple-input multiple-output (MIMO) systems is a technique to
reduce cost and power consumption. In this context, nevertheless, it has been
shown that the training duration is required to be {\em very large} just to
obtain an acceptable channel state information (CSI) at the receiver. A
possible solution to the quantized MIMO systems is joint channel-and-data (JCD)
estimation. This paper first develops an analytical framework for studying the
quantized MIMO system using JCD estimation. In particular, we use the
Bayes-optimal inference for the JCD estimation and realize this estimator
utilizing a recent technique based on approximate message passing. Large-system
analysis based on the replica method is then adopted to derive the asymptotic
performances of the JCD estimator. Results from simulations confirm our
theoretical findings and reveal that the JCD estimator can provide a
significant gain over conventional pilot-only schemes in the quantized MIMO
system.Comment: 7 pages, 4 figure
3-Methyl-1-(3-nitrophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole
In the title compound, C16H15N3O2, the planar [maximum deviation 0.156 (2) Å] pyrazoline ring is nearly coplanar with the 3-nitrophenyl group and is approximately perpendicular to the phenyl ring, making dihedral angles of 3.80 (8) and 80.58 (10)°, respectively. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure
5-(2-Furyl)-3-methyl-1-(3-nitrophenyl)-4,5-dihydro-1H-pyrazole
In the title compound, C14H13N3O3, the pyrazoline ring assumes an envelope conformation with the furanyl-bearing C atom at the flap position. The dihedral angle between the furan and nitrobenzene rings is 84.40 (9)°. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure
Room-Temperature Spin-Valve Effect in FeGaTe/MoS/FeGaTe 2D van der Waals Heterojunction Devices
Spin-valve effect has been the focus of spintronics over the last decades due
to its potential in many spintronic devices. Two-dimensional (2D) van der Waals
(vdW) materials are highly expected to build the spin-valve heterojunction.
However, the Curie temperatures (TC) of the vdW ferromagnetic 2D crystals are
mostly below room temperature (~30-220 K). It is very challenging to develop
room temperature, ferromagnetic (FM) 2D crystals based spin-valve devices which
are still not available to date. We report the first room temperature, FM 2D
crystal based all-2D vdW Fe3GaTe2/MoS2/Fe3GaTe2 spin valve devices. The
Magnetoresistance (MR) of the all- devices is up to 15.89% at 2.3 K and 11.97%
at 10 K, 4-30 times of MR from the spin valves of
FeGaTe/MoS/FeGaTe and conventional NiFe/MoS/NiFe.
Typical spin valve effect shows strong dependence on MoS2 spacer thickness in
the vdW heterojunction. Importantly, the spin valve effect (0.31%) still
robustly exists at 300 K with low working currents down to 10 nA (0.13
A/cm). The results provide a general vdW platform to room temperature, 2D
FM crystals based 2D spin valve devices
Room-temperature and tunable tunneling magnetoresistance in Fe3GaTe2-based all-2D van der Waals heterojunctions with high spin polarization
Magnetic tunnel junctions (MTJs) based on all-two dimensional (2D) van der
Waals heterostructures with sharp and clean interfaces in atomic scale are
essential for the application of next-generation spintronics. However, the lack
of room-temperature intrinsic ferromagnetic crystals with perpendicular
magnetic anisotropy has greatly hindered the development of vertical MTJs. The
discovery of room-temperature intrinsic ferromagnetic 2D crystal Fe3GaTe2 has
solved the problem and greatly facilitated the realization of practical
spintronic devices. Here, we demonstrate a room-temperature MTJ based on
Fe3GaTe2/WS2/Fe3GaTe2 heterostructure. The tunnelling magnetoresistance (TMR)
ratio is up to 213% with high spin polarization of 72% at 10 K, the highest
ever reported in Fe3GaTe2-based MTJs up to now. The tunnelling spin-valve
signal robustly exists at room temperature (300 K) with bias current down to 10
nA. Moreover, the spin polarization can be modulated by bias current and the
TMR shows a sign reversal at large bias current. Our work sheds light on the
potential application for low-energy consumption all-2D vdW spintronics and
offers alternative routes for the electronic control of spintronic devices
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