scholarly journals Production, detection, storage and release of spin currents

2015 ◽  
Vol 6 ◽  
pp. 736-743 ◽  
Author(s):  
Michele Cini
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Spin Current ◽  
Optical Excitation ◽  
Pure Spin ◽  
Field Methods ◽  
Magnetic Current ◽  
Spin Currents ◽  
New Phenomena ◽  
Storage Units

Background: Quantum rings connected to ballistic circuits couple strongly to external magnetic fields if the connection is not symmetric. Moreover, properly connected rings can be used to pump currents in the wires giving raise to a number of interesting new phenomena. At half filling using a time-dependent magnetic field in the plane of the ring one can pump a pure spin current, excited by the the spin–orbit interaction in the ring. Results: Such a magnetic current is even under time reversal and produces an electric field instead of the usual magnetic field. Numerical simulations show that one can use magnetizable bodies as storage units to concentrate and save the magnetization in much the same way as capacitors operating with charge currents store electric charge. The polarization obtained in this way can then be used on command to produce spin currents in a wire. These currents show interesting oscillations while the storage units exchange their polarizations. Conclusion: The magnetic production of spin currents can be a useful alternative to optical excitation and electric field methods.

scholarly journals Generation of Spin Currents by Magnetic Field in 𝒯- and 𝒫-Broken Materials

SPIN ◽  
2019 ◽  
Vol 09 (04) ◽  
pp. 1940013 ◽  
Author(s):  
Jing Wang ◽  
Biao Lian ◽  
Shou-Cheng Zhang
Keyword(s):  
Magnetic Field ◽  
Spin Current ◽  
Quantum Spin ◽  
Pure Spin ◽  
Heusler Compounds ◽  
Spin Currents ◽  
Dirac Semimetal ◽  
Low Energy Consumption ◽  
And Inversion ◽  
The Magnetic Field

Pure spin currents carry information in quantum spintronics and could play an essential role in the next generation low-energy-consumption electronics. Here, we theoretically predict that the magnetic field can induce a quantum spin current without a concomitant charge current in metals without time reversal symmetry [Formula: see text] and inversion symmetry [Formula: see text] but respect the combined [Formula: see text] symmetry. It is governed by the magnetic moment of the Bloch states on the Fermi surface, and can be regarded as a spinful generalization of the gyrotropic magnetic effect in [Formula: see text]-broken metals. The effect is explicitly studied for a minimal model of an antiferromagnetic Dirac semimetal, where the experimental signature is proposed. We further propose candidate materials, including topological antiferromagnetic Dirac semimetals, Weyl semimetals and tenary Heusler compounds.

Spin Hall Effect in a Magnetic Field

2001 ◽  
Vol 690 ◽  
Author(s):  
Shufeng Zhang
Keyword(s):  
Magnetic Field ◽  
Diffusion Equation ◽  
Electric Field ◽  
Hall Effect ◽  
Transverse Electric ◽  
Spin Current ◽  
Magnetic Semiconductor ◽  
Hall Voltage ◽  
Spin Polarized ◽  
The Magnetic Field

ABSTRACTWhen a spin-polarized current is injected into a non-magnetic semiconductor, a transverse electric field known as Hall voltage is generated. By using a macroscopic diffusion equation, we derive the Hall voltage in the presence of both spin current and magnetic field. Novel features such as oscillating Hall signals as a function of the magnetic field and geometrical dependence of Hall signals are predicted.

Spin currents in semiconductor nanostructures: A non-equilibrium Green-function approach

2017 ◽  
Author(s):  
Branislav K. Nikolic ◽  
Liviu P. Zarbo ◽  
Satofumi Souma
Keyword(s):  
Green Function ◽  
Spin Current ◽  
Semiconductor Nanostructures ◽  
Pure Spin ◽  
Current Operator ◽  
Spin Orbit ◽  
Spin Currents ◽  
Low Dimensional ◽  
Green Function Approach ◽  
Non Equilibrium

This article examines spin currents and spin densities in realistic open semiconductor nanostructures using different tools of quantum-transport theory based on the non-equilibrium Green function (NEGF) approach. It begins with an introduction to the essential theoretical formalism and practical computational techniques before explaining what pure spin current is and how pure spin currents can be generated and detected. It then considers the spin-Hall effect (SHE), and especially the mesoscopic SHE, along with spin-orbit couplings in low-dimensional semiconductors. It also describes spin-current operator, spindensity, and spin accumulation in the presence of intrinsic spin-orbit couplings, as well as the NEGF approach to spin transport in multiterminal spin-orbit-coupled nanostructures. The article concludes by reviewing formal developments with examples drawn from the field of the mesoscopic SHE in low-dimensional spin-orbit-coupled semiconductor nanostructures.

Studies of spin related processes in fullerene C60 devices

2018 ◽  
Vol 6 (14) ◽  
pp. 3621-3627 ◽  
Author(s):  
Haoliang Liu ◽  
Jingying Wang ◽  
Matthew Groesbeck ◽  
Xin Pan ◽  
Chuang Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Spin Current ◽  
Fullerene C60 ◽  
Spin Valves ◽  
Pure Spin ◽  
Carrier Injection ◽  
Current Generation ◽  
Spin Polarized

We have investigated spin related processes in fullerene C60 devices using a several experimental techniques, which include magnetic field effect of photocurrent and electroluminescence in C60-based diodes; spin polarized carrier injection in C60-based spin-valves; and pure spin current generation in NiFe/C60/Pt trilayer devices.

scholarly journals TEMPERATURE DEPENDENCE OF SPIN CURRENTS CARRIED BY JORDAN–WIGNER FERMIONS AND MAGNONS IN INSULATORS

2012 ◽  
Vol 26 (01) ◽  
pp. 1250011
Author(s):  
KOUKI NAKATA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Temperature Dependence ◽  
Magnetic Field Gradient ◽  
Particle Interaction ◽  
Three Dimensional ◽  
Spin Current ◽  
One Dimensional ◽  
Spin Currents ◽  
The One

The temperature dependence of spin currents in insulators at the finite temperature near zero Kelvin is theoretically studied. The spin currents are carried by Jordan–Wigner fermions and magnons in one- and three-dimensional insulators. These spin currents are generated by the external magnetic field gradient along the quantization axis and also by the two-particle interaction gradient. In one-dimensional insulators, quantum fluctuations are strong and the spin current carried by Jordan–Wigner fermions shows the stronger dependence on temperatures than the one by magnons.

Calculation of the pulsed electromagnetic field of a plane annular magnetic current

Antennas ◽  
2021 ◽  
Author(s):  
I. P. Kovalyov ◽  
N. I. Kuzikova
Keyword(s):  
Magnetic Field ◽  
Fourier Transform ◽  
Electric Field ◽  
Wave Front ◽  
Time Domain ◽  
Vector Potential ◽  
Magnetic Current ◽  
The Fourier Transform ◽  
The Time Domain ◽  
The Magnetic Field

The work calculates the radiation fields of a plane ring magnetic current in the time domain. Two functions are considered that describe the dependence of the magnetic current on time: the delta function and the unit drop. All calculations are performed in the time domain without using the Fourier transform. First, the time-dependent vector potential is calculated. When writing expressions for the vector potential, the annular magnetic current is represented by the difference between two circular magnetic currents. Then, the magnetic field created by the ring magnetic current is found through the vector potential. Only one φ-th component of the magnetic field is nonzero. Further, from Maxwell's equations through the magnetic field, the components of the electric field of the annular magnetic current are calculated. On the basis of the formulas obtained, various special cases showing the dependence of the emitted field on time and spatial coordinates are considered. The time dependence of the electric field on the ring axis is calculated. It is shown that the Fourier transform of this field leads to a formula known from the literature in the frequency domain for calculating the field on the axis of the ring. The graphs are given showing that near the wave front, the transverse components of the electric and magnetic fields differ only by a factor equal to the wave resistance of the medium (120π for the air medium). The images of the electric field at different times are shown. In the given pictures of the fields, one can observe the movement of the radiation field near the wave front and the formation of a static field in the vicinity of the ring. The analytical expressions obtained in this work can be used to calculate antennas and other structures excited by a coaxial line. They can be used to solve integral equations in the time domain.

scholarly journals Manipulation of spin currents in metallic systems

2011 ◽  
Vol 369 (1948) ◽  
pp. 3136-3149 ◽  
Author(s):  
Yoshichika Otani ◽  
Takashi Kimura
Keyword(s):  
Room Temperature ◽  
Spin Diffusion ◽  
Diffusion Processes ◽  
Spin Injection ◽  
Spin Current ◽  
Hybrid Structures ◽  
Pure Spin ◽  
Spin Currents ◽  
Magnetic Metal ◽  
Hall Effect Measurements

The transport properties of diffusive spin currents have been investigated in lateral ferromagnetic/non-magnetic metal hybrid structures. The spin diffusion processes were found to be strongly dependent on the magnitude of the spin resistances of connected materials. Efficient spin injection and detection are accomplished by optimizing the junction structures on the basis of the spin resistance circuitry. The magnetization switching of a nanoscale ferromagnetic particle and also room temperature spin Hall effect measurements were realized by using an efficient pure-spin-current injection.

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽  
2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauludi Manfaluthy
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Energy Utilization ◽  
World Health ◽  
Electromagnetic Signals ◽  
Health Organization ◽  
The Magnetic Field ◽  
Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under  100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and  LED Module.

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