57 results on '"S. G. Chigarev"'
Search Results
2. Thermal and Dynamic Radiation in the THz Range Under Spin Current Injection in Magnetic Junctions
- Author
-
S. G. Chigarev, L. A. Fomin, D. P. Rai, E. A. Vilkov, O. A. Byshevsky-Konopko, D. L. Zagorsky, I. M. Doludenko, and A. I. Panas
- Subjects
Electrical and Electronic Engineering ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Abstract
An experimental approach to the problem of the energy distribution of radiation in the THz range created by an electron flow passing through a magnetic junction between thermal and dynamic is considered. The experimental results obtained during the operation of a spin-injection emitter based on an array of heterogeneous magnetic nanowires (NWs) confirmed the assumption about the “competition” of thermal and dynamic radiation processes.
- Published
- 2023
3. Ensembles of Layered Nanowires, Obtained by Matrix Synthesis Technique, for Generation of THz Irradiation
- Author
-
Andrey.I Panas, Vladimir M. Kanevskii, Dmitrii L. Zagorskiy, Evgeny A. Vilkov, S. G. Chigarev, and Ilia M. Doludenko
- Subjects
Range (particle radiation) ,Materials science ,Terahertz radiation ,business.industry ,Nanowire ,STRIPS ,Radiation ,Electronic, Optical and Magnetic Materials ,law.invention ,Metal ,Condensed Matter::Materials Science ,law ,visual_art ,visual_art.visual_art_medium ,Galvanic cell ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,Irradiation ,Electrical and Electronic Engineering ,business - Abstract
Ensembles of parallel nanowires, consists of the parts from different ferro-magnetic metals (for example-FeNi/Co/FeNi) were obtained by method of template synthesis. It was shown that such samples could be the sources of electromagnetic emission – irradiation of Terahertz range. It could be detected when current passed through the contacts at the sample with these wires. The methods of obtaining nanowires was proposed (two-bath galvanic technique), formation of contact layers at the surface (parallel narrow strips of metal) were proposed. The features of these radiation were investigated–it‘s threshold character, it‘s non-thermal origin and spatial distribution. The calculation was also presented, which demonstrated possibility of detecting of Terahertz irradiation, using ensemble of such nanowires, included ferro-magnetic metal and anti-ferromagnetic metal.
- Published
- 2022
4. Terahertz Radiation in the Fe/Mo Magnetic Transition
- Author
-
E. A. Vilkov, S. G. Chigarev, I. V. Malikov, and L. A. Fomin
- Subjects
Condensed Matter Physics ,Electronic, Optical and Magnetic Materials - Published
- 2021
5. Thermal and Dynamic Radiation in the THz range under Spin CurrentInjection in Magnetic Junctions
- Author
-
S. G. Chigarev, L. A. Fomin, D. P. Rai, E. A. Vilkov, O. A. Byshevsky-Konopko, D. L. Zagorsky, I. M. Doludenko, and A. I. Panas
- Abstract
An experimental approach to the problem of the energy distribution of radiation in the THz range created by an electron flow passing through a magnetic junction between thermal and dynamic is considered. The experimental results obtained during the operation of a spin-injection emitter based on an array of heterogeneous magnetic nanowires confirmed the assumption about the "competition" of thermal and dynamic radiation processes.
- Published
- 2022
6. Electromagnetic Radiation under Spin Injection in a Tunnel Magnetic Junction with a NiO Spacer
- Author
-
S. G. Chigarev, E. A. Vilkov, S. N. Maryshev, I. V. Malikov, and A. V. Chernykh
- Subjects
010302 applied physics ,Radiation ,Materials science ,business.industry ,Non-blocking I/O ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,01 natural sciences ,Electromagnetic radiation ,Electronic, Optical and Magnetic Materials ,Tunnel magnetoresistance ,Potential difference ,Condensed Matter::Superconductivity ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Physics::Accelerator Physics ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,business ,Spin injection ,Common emitter - Abstract
The operation of a spin-injection emitter of electromagnetic oscillations with a Ni/NiO/Fe magnetic tunnel junction was first investigated. Using a nonconducting NiO spacer in a magnetic junction, the effect of the potential difference at the interface between magnetic layers on the efficiency of spin-injection emitters is determined. A model of the investigated emitter is theoretically described and the efficiencies of the emitters with a magnetic tunnel junction and a magnetic junction without an Ni/Fe spacer are experimentally compared. The possibility of enhancing the efficiency of the spin-injection emitter by using the magnetic tunnel junction is demonstrated.
- Published
- 2021
7. Appearance of Intrinsic Magnetization in FeMn Antiferromagnetic Film under the Action of Spin-Polarized Current
- Author
-
E A Vilkov, S G Chigarev, Production Enterprise, Fryazino, Moscow oblast, Russian Federation, O.A. Byshevski-Konopko, and A.I. Panas
- Subjects
Physics ,Magnetization ,Condensed matter physics ,Control and Systems Engineering ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) ,Action (physics) ,Spin-½ - Abstract
The article presents the results of research of two spin-injection sources of THz radiation using different structures of thin-film magnetic transitions (MT) with antiferromagnetic (AFM) FeMn film of nanoscale thickness and ferromagnetic (FM) Fe layer. In both variants, the possibility of intrinsic magnetization forming in the AFM film under the action of a spin-polarized current of a relatively small value formed in the FM layer is shown. The physical foundations of this effect based on the AFM sublattices beveling by a spin-polarized current due to the sd-exchange interaction of the conduction electrons spins with the spins of d electrons of the FM crystal lattice are considered. This does not require an external magnetic field. sd-exchange mechanism of excitation of intrinsic magnetization in AFM is an alternative to the spin-orbit mechanism, which has been widely considered recently. The relations for calculating the frequency and power of spin-injection radiation are given. New experimental results have been obtained that develop the concept of the AFM's intrinsic magnetization. The non-thermal nature of spin-injection radiation and the possibility of increasing the efficiency of the emitter operation due to the ordering of the MT structure by an external magnetic field are shown. The way of increasing the efficiency of spin-injection emitters by creating structures with multiple independently operating micro-emitters at frequencies close to 16 THz and with a signal power of up to a hundred microwatts has been determined. In general, it is shown that the use of the effect of excitation of intrinsic magnetization in AFM is of interest, both from the point of view of the development of theoretical ideas about the magnetic properties of AFM, and from a practical point of view for the creation of spin-injection lasers (tasers).
- Published
- 2020
8. Injectional Equilibrium Spin Polarization in a Magnetic Transition, Taking into Account the Electron Spin Mobility
- Author
-
O. A. Byshevsky-Konopko, Ansar R. Safin, L. A. Fomin, E. A. Vilkov, S. G. Chigarev, and S. A. Nikitov
- Subjects
010302 applied physics ,Physics ,Radiation ,Condensed matter physics ,Spin polarization ,Terahertz radiation ,Non-equilibrium thermodynamics ,020206 networking & telecommunications ,02 engineering and technology ,Electron ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Ferromagnetism ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) ,Current density ,Order of magnitude - Abstract
Taking into account the electron spin mobility, the paper considers the numerical solution to the equation for nonequilibrium spin polarization at the boundary of a magnetic contact with a current formed by two ferromagnets. The frequencies of spin injection radiation are calculated. It is shown that at a certain current density exceeding the threshold value, these frequencies lie in the terahertz frequency range. It was found that for the same terahertz frequency range, even for small values of the difference in the mobility of electrons with spin up and down, the current density can be two orders of magnitude lower than the current density with the same mobility.
- Published
- 2020
9. Frequency of Spin-Injection Radiation in the Magnetic Junction as a Function of the Spin Mobility of Electrons
- Author
-
S. A. Nikitov, L. A. Fomin, Ansar R. Safin, O. A. Byshevskii-Konopko, E. A. Vilkov, and S. G. Chigarev
- Subjects
010302 applied physics ,Electron mobility ,Materials science ,Condensed matter physics ,Spin polarization ,Terahertz radiation ,Electron ,Radiation ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Ferromagnetism ,0103 physical sciences ,010306 general physics ,Current density ,Spin-½ - Abstract
Taking into account the difference in the mobilities of electrons with different spin projections, the frequencies of spin-injection radiation in the current-carrying magnetic contact formed by two ferromagnets are calculated. It is shown that these frequencies are in the terahertz range at a certain current density exceeding the threshold value, and the current density required to generate terahertz radiation can be, even at small values of the electron mobility difference, two orders of magnitude less than that in the absence of the electron mobility difference. The effect of the spin polarization ratio of ferromagnets that form a magnetic junction on the radiation frequency is analyzed.
- Published
- 2020
10. Effect of a Potential Jump in a Magnetic Junction upon Spin Injection by an Electric Current on the Effectiveness of Electromagnetic Wave Radiation
- Author
-
S. G. Chigarev and E. A. Vilkov
- Subjects
010302 applied physics ,Imagination ,Materials science ,Condensed matter physics ,010308 nuclear & particles physics ,media_common.quotation_subject ,Hadron ,Non-blocking I/O ,General Physics and Astronomy ,Radiation ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Electromagnetic radiation ,Condensed Matter::Superconductivity ,0103 physical sciences ,Jump ,Condensed Matter::Strongly Correlated Electrons ,Electric current ,media_common ,Fermi Gamma-ray Space Telescope - Abstract
Results are presented from studying the effect a jump in potential has on the modes of operation of different magnetic junctions, including the Ni/NiO/Fe tunnel magnetic junction. The difference between the effectiveness of radiation in them is explained by the effect of jumps in potential have on the formation of Fermi quasi-levels in spin-energy sub-bands.
- Published
- 2020
11. Spin Polarization of Nonequilibrium Conduction Electrons in Magnetic Junctions
- Author
-
M. V. Logunov, S. G. Chigarev, E. A. Vilkov, and S. A. Nikitov
- Subjects
010302 applied physics ,Physics ,Radiation ,Spin polarization ,Magnetic moment ,Condensed matter physics ,Non-equilibrium thermodynamics ,020206 networking & telecommunications ,02 engineering and technology ,Electron ,Condensed Matter Physics ,Thermal conduction ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Atomic electron transition ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Absorption (electromagnetic radiation) ,Spin-½ - Abstract
An original equation for nonequilibrium spin polarization in magnetic junctions based on dynamic equations for magnetic moment was obtained. Spatial nonuniformity of the distribution of carriers is taken into account in the equations, and the magnetic moment is averaged over the ensemble of nonequilibrium spin-injected electrons. The solution to the dynamic equations for the magnetic moment is used to estimate the probability of spin-flip electron transitions upon spin injection, and the solution to the equation for the nonequilibrium spin polarization in magnetic junctions is used to calculate frequencies of photon emission or absorption at energies corresponding to the energy of effective exchange splitting of spin subbands.
- Published
- 2019
12. Dynamics of Spatially Inhomogeneous Spin Polarization of Nonequilibrium Conduction Electrons in Magnetic Transitions
- Author
-
L. A. Fomin, Ansar R. Safin, M. V. Logunov, E. A. Vilkov, S. A. Nikitov, Gennady M. Mikhailov, Vladislav N. Korenivskii, and S. G. Chigarev
- Subjects
010302 applied physics ,Electromagnetic field ,Materials science ,Spin polarization ,Magnetic moment ,Condensed matter physics ,Exchange interaction ,Electron ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Ferromagnetism ,0103 physical sciences ,Charge carrier ,010306 general physics ,Anisotropy - Abstract
The equation of the dynamics of the magnetic moment motion that has been averaged over the ensemble of nonequilibrium spin-injected electrons in a ferromagnetic transition in the presence of exchange interaction, interaction with an external electromagnetic field, and a thermostat has been obtained taking into account the spatial inhomogeneity of the charge carrier distribution. It has been shown that taking into account the spatial inhomogeneity of the charge carrier distribution in the equation of the dynamics of the magnetic moment motion allows for describing the various processes of electron transfer in the magnetic transition. The probability of quantum transitions of electrons with opposite spin directions, which determine spin relaxation in interaction with a thermostat, has been estimated. It has been shown that the anisotropy of the radiation medium is determined not only by the anisotropy of the sd-exchange tensor, but also by the additional anisotropy that is caused by the electron impulse derivatives of this tensor. The considered phenomena have a great potential for the detection of new effects and development of new devices based on them, including compact tunable radiation sources in the terahertz frequency range, which is obviously difficult to generate.
- Published
- 2019
13. Spin Polarization Dynamics of Nonequilibrium Conduction Electrons in Magnetic Junctions
- Author
-
Ansar R. Safin, E. A. Vilkov, M. V. Logunov, S. A. Nikitov, Vladislav N. Korenivskii, S. G. Chigarev, L. A. Fomin, and Gennady M. Mikhailov
- Subjects
010302 applied physics ,Physics ,Photon ,Condensed matter physics ,Spin polarization ,Magnetic moment ,Exchange interaction ,Relaxation (NMR) ,General Physics and Astronomy ,Electron ,01 natural sciences ,Ferromagnetism ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,Spin (physics) - Abstract
The dynamics of the motion of the magnetic moment averaged over an ensemble of nonequilibrium spin-injected electrons in a ferromagnetic junction is considered with allowance for the exchange interaction, as well as the interaction with an external electromagnetic field and a thermostat. The solution of this problem is important for the experimental development of compact terahertz-band radiation sources. The rate of quantum transitions of electrons with opposite spins, which determine the spin relaxation under the interaction with a thermostat, is calculated within the density matrix formalism. It is shown that two spin-relaxation modes can be implemented that correspond to low- and high-Q precession of spin-nonequilibrium injected electrons. The effect of the characteristic features of spin-flip transitions under the relaxation of the magnetic moment on the emission and absorption of photons with-energy corresponding to the energy of effective exchange splitting of spin subbands is discussed.
- Published
- 2018
14. Increasing the Efficiency of Terahertz Generation during the Current Flow through Magnetic Junctions Formed by Inhomogeneous Ultrathin Films of a Ferromagnetic Metal
- Author
-
N. N. Udalov, A. V. Chernykh, Gennady M. Mikhailov, S. V. Il’in, E. A. Vilkov, A. G. Kolesnikov, A. V. Ognev, S. G. Chigarev, Yu. V. Gulyaev, Ansar R. Safin, R. S. Kulikov, and R. S. Davydenko
- Subjects
010302 applied physics ,Radiation ,Materials science ,business.industry ,Terahertz radiation ,020206 networking & telecommunications ,02 engineering and technology ,Conductivity ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Metal ,Ferromagnetism ,visual_art ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,Optoelectronics ,Electrical and Electronic Engineering ,Current (fluid) ,business ,Electrical conductor ,Current density - Abstract
Operating modes of terahertz (THz) generators with “rod–film” magnetic junctions formed by a Fe rod with one pointed end with a diameter of 10–50 nm and various nanometer-thick (single-layer and multilayer) Со films are studied. It is demonstrated that the efficiency of the THz radiation increases (due to an increase in the current density) if the thickness of a single-layer film decreases to the point when it becomes discontinuous (ultrathin) while retains its conductivity. If a multilayer structure with several such films separated by nonmagnetic conductive layers is used, the radiation power can also be increased.
- Published
- 2018
15. Generation of Terahertz Radiation in Magnetic Junctions Based on Nanowires
- Author
-
D. L. Zagorskii, A. I. Panas, A. S. Shatalov, Yu. V. Gulyaev, N. A. Maksimov, E. A. Vilkov, and S. G. Chigarev
- Subjects
010302 applied physics ,Range (particle radiation) ,Manufacturing technology ,Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Terahertz radiation ,Nanowire ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nanowire array ,0103 physical sciences ,Optoelectronics ,0210 nano-technology ,business - Abstract
A system of spin-injection emitters employing magnetic junctions based on an array of parallel nanodimensional wires has been studied. Manufacturing technology and possible variants of the nanowire structure are discussed. Conditions of the formation of a new type of spin-injection emitters of terahertz radiation on this basis are considered. The design of the experimental setup is described, and the results of experiments are analyzed. It is established that signals in a 16–18 THz range can be generated by passing high-density current through the proposed nanowire array.
- Published
- 2019
16. THz radiation spectra in magnetic Fe/Mo and Fe/Co2FeAl junctions
- Author
-
L. A. Fomin, I V Malikov, E A Vilkov, and S G Chigarev
- Subjects
History ,Materials science ,Thz radiation ,Molecular physics ,Spectral line ,Computer Science Applications ,Education - Published
- 2021
17. Stimulated terahertz emission
- Author
-
E. A. Vilkov, P. E. Zilberman, A. V. Chernykh, Yu. V. Gulyaev, Gennady M. Mikhailov, and S. G. Chigarev
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Spins ,business.industry ,Terahertz radiation ,Physics::Optics ,Condensed Matter Physics ,Laser ,Electronic, Optical and Magnetic Materials ,law.invention ,Ferromagnetism ,law ,Antiferromagnetism ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) ,business ,Order of magnitude - Abstract
The observation of the stimulated terahertz radiation in magnetic junctions at the room temperature resulting from the current injection of nonequilibrium spins is reported. Contacts between two ferromagnetic layers and between a ferromagnetic and an antiferromagnetic layer are investigated. As the current is increased, first, a narrow isolated radiation peak at terahertz frequencies is observed, which is analogous to the laser peak; then, the peak broadens and its intensity increases by more than an order of magnitude.
- Published
- 2015
18. A spin-injection terahertz generator based on the metatransition monolithic structure
- Author
-
E. A. Vilkov, I. V. Malikov, Gennady M. Mikhailov, S. G. Chigarev, A. I. Panas, P. E. Zilberman, A. V. Chernykh, and Yu. V. Gulyaev
- Subjects
Radiation ,Materials science ,business.industry ,Terahertz radiation ,Physics::Medical Physics ,Structure (category theory) ,Physics::Optics ,Nanoparticle ,Condensed Matter Physics ,Electromagnetic radiation ,Electronic, Optical and Magnetic Materials ,Generator (circuit theory) ,Planar ,Antiferromagnetism ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) ,business - Abstract
The possibility of generation of terahertz electromagnetic waves by the current in a planar structure composed of metalferromagnetic nanoparticles imbedded into an antiferromagnetic medium, is considered.
- Published
- 2015
19. Spin-Injection Stimulated Radiation of Terahertz Waves in Magnetic Junctions ('Twaser' Action)
- Author
-
E. A. Vilkov, P. E. Zilberman, A. I. Panas, Yu. V. Gulyaev, S. G. Chigarev, A.V. Chernych, and Gennady M. Mikhailov
- Subjects
education.field_of_study ,Materials science ,Condensed matter physics ,Spins ,Terahertz radiation ,Population ,Condensed Matter Physics ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Resonator ,Ferromagnetism ,law ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,General Materials Science ,Stimulated emission ,education - Abstract
We report on apparently the first observation of terahertz stimulated radiation in magnetic junctions due to nonequilibrium spins injected by current at room temperatures. The contact between ferromagnetic layers is investigated and so the contact between ferromagnetic and antiferromagnetic layers. The current flowing in the structure creates an inversed population of spin energy levels. After a placing of such a structure in a resonator positive feedback and stimulated emission appears. When current is growing, we observe the relatively narrow (in frequencies) peak - analogous to laser generation but at terahertz frequencies. For the higher currents we observe the picture of electromagnetic turbulence.
- Published
- 2015
20. Spin-injection generators of terahertz waves based on metal magnetic structures
- Author
-
P. E. Zilberman, Yu. V. Gulyaev, and S. G. Chigarev
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Terahertz radiation ,Resonance ,Condensed Matter Physics ,Electromagnetic radiation ,Instability ,Electronic, Optical and Magnetic Materials ,Magnetization ,Ferromagnetism ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) - Abstract
Fundamentally new devices for the generation of terahertz waves due to the effect of the spin-polarized current in ferromagnetic and antiferromagnetic metal structures (magnetic junctions) are considered. The spin injection and the sd exchange and its effect on the interaction with electromagnetic waves play the main role in such devices. The effects that are induced by the polarized current in the antiferromagnetic materials (exchange instability, induced magnetization, and spin-injection antiferromagnetic resonance) are discussed. The principles and effects of the generation of the terahertz electromagnetic oscillations are considered, and the characteristics of the experimental prototypes of the corresponding devices are analyzed.
- Published
- 2015
21. Base Constructions and Experimental Working Characteristics of Nano- and Micro-Sized Terahertz Wave Generators on 3–30 THz
- Author
-
S. G. Chigarev, E. A. Vilkov, A. I. Panas, P. E. Zilberman, Yu. V. Gulyaev, A. V. Chernykh, Gennady M. Mikhailov, and V.I. Malikov
- Subjects
Materials science ,business.industry ,Terahertz radiation ,Nano ,Optoelectronics ,Mechanical engineering ,General Medicine ,business ,Base (topology) ,Terahertz metamaterials - Published
- 2015
22. The magnetostatic field in a terahertz rod/film structure
- Author
-
S. G. Chigarev, E A Vilkov, Sergey G. Moiseev, and P. E. Zilberman
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Lateral surface ,Field (physics) ,business.industry ,Terahertz radiation ,Electron ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Optics ,Ferromagnetism ,Radiative transfer ,Electrical and Electronic Engineering ,Current (fluid) ,business - Abstract
The magnetostatic field distribution in a structure formed from a ferromagnetic (FM) rod and thin FM film is numerically calculated. The effective terahertz radiation was previously discovered in such a structure in the presence of a current. It is shown that nanodimensional sections of the boundary between the lateral surface of the rod and the surface of the film can be a source of radiation. On these sections, the magnetostatic field changes its direction, a circumstance that provides for conditions for radiative transitions of electrons.
- Published
- 2014
23. Spin-injection stimulated emission of terahertz waves in magnetic junctions
- Author
-
E. A. Vilkov, Gennady M. Mikhailov, A. V. Chernykh, S. G. Chigarev, P. E. Zilberman, and Yu. V. Gulyaev
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Ferromagnetism ,Solid-state physics ,Condensed matter physics ,Spins ,Terahertz radiation ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Stimulated emission ,Population inversion ,Spin (physics) - Abstract
The stimulated emission of terahertz radiation in magnetic junctions at room temperature resulting from the current injection of nonequilibrium spins is observed. Contacts between two ferromagnetic layers as well as between a ferromagnetic and an antiferromagnetic layer are investigated. The current produces the population inversion of spin energy levels. As the system is placed in a cavity, positive feedback and stimulated emission appear. The development of a dominant emission peak and onset of electromagnetic turbulence are observed.
- Published
- 2014
24. Pulsed regime of a spin-injection oscillator
- Author
-
I. V. Malikov, Gennady M. Mikhailov, S. G. Chigarev, and A. V. Chernykh
- Subjects
Physics ,Radiation ,Terahertz radiation ,Condensed Matter Physics ,Signal ,Electronic, Optical and Magnetic Materials ,Pulse (physics) ,Chopper ,Nuclear magnetic resonance ,Transducer ,Electrical and Electronic Engineering ,Current (fluid) ,Atomic physics ,Common emitter - Abstract
A spin-injection oscillator in the pulsed regime is studied for the first time at different time parameters of current pulses using an opto-acoustic transducer in the absence of chopper. The reciprocity principle is violated when the direction of current in the pulse is reversed in the pulsed regime of the terahertz generation. The radiation signal of the spin-injection emitter is proportional to the number of charges that are injected by a current pulse and does not depend on the energy that is released in the presence of the pulsed current flow.
- Published
- 2014
25. Spin Injection Mechanisms for Radiation and Detection of Terahertz Waves Based on Magnetic Nano Junction
- Author
-
S. G. Chigarev, Petr E. Zilberman, and E. A. Vilkov
- Subjects
Materials science ,business.industry ,Terahertz radiation ,Far-infrared laser ,Physics::Optics ,Radiation ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Terahertz spectroscopy and technology ,Photomixing ,Nano ,Optoelectronics ,General Materials Science ,Terahertz time-domain spectroscopy ,Spin (physics) ,business - Abstract
Spin injection mechanisms for radiation and detection of terahertz waves based on magnetic nano junction are considered. High efficiency of terahertz radiation is theoretically explained and the method of the detection of this radiation is offered. The device of the spin injected terahertz radiators is presented.
- Published
- 2014
26. Generation of terahertz waves by a current in magnetic junctions
- Author
-
Gennady M. Mikhailov, S. G. Chigarev, P. E. Zilberman, and Yu. V. Gulyaev
- Subjects
Physics ,education.field_of_study ,Terahertz gap ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Solid-state physics ,Terahertz radiation ,Population ,Electron ,Magnetic field ,Magnetization ,Ferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,education - Abstract
The terahertz region of the electromagnetic spectrum (approximately 0.3–30 THz) is still insufficiently mastered primarily because of the absence of compact and controllable emitters (oscillators) and receivers (detectors) reliably operating in this range in a wide temperature range, including room temperature. The corresponding recent studies in this field, which were supported by the Russian Foundation for Basic Research, have been reviewed. New physical effects have been proposed and principles of the operation of terahertz devices based on these effects have been implemented. These effects refer to the physics of ferromagnetic and/or antiferromagnetic conducting layers assembled in micro- and nanostructures, which are called magnetic junctions. These effects are as follows: the formation of a quasiequilibrium distribution of current-injected electrons over the energy levels and the possibility of inverted population of levels, induction of the macroscopic magnetization by a spin-polarized current in an antiferromagnetic layer in the absence of external magnetic field, the appearance of current-induced contribution to antiferromagnetic resonance, and the experimental observation and study of the properties of terahertz radiation in ferromagnet-ferromagnet and ferromagnet-antiferromagnet junctions.
- Published
- 2014
27. sd-Exchange emission in ferromagnetic junctions
- Author
-
E. A. Vilkov, S. G. Chigarev, P. E. Zilberman, Yu. V. Gulyaev, and Gennady M. Mikhailov
- Subjects
Electromagnetic field ,Physics ,Magnetization ,Radiation ,Radiation frequency ,Ferromagnetism ,Condensed matter physics ,Terahertz radiation ,Electrical and Electronic Engineering ,Atomic physics ,Condensed Matter Physics ,Spin (physics) ,Electronic, Optical and Magnetic Materials - Abstract
The spin-injection emission in a ferromagnetic junction at terahertz frequencies is theoretically analyzed. It is demonstrated that the efficiency of the emission caused by the sd-exchange interaction of the injected spin in which the electromagnetic field is involved strongly depends on the orientation angle of the magnetization of the active region relative to the magnetization direction of the injecting region. The fact that the calculated radiation frequency and power are close to the experimental results shows that the sd-exchange emission must be taken into account in the interpretation of the observed terahertz emission in magnetic junctions.
- Published
- 2013
28. Detection and generation of submillimeter and terahertz modes in ferromagnet-antiferromagnet junctions
- Author
-
P. E. Zilberman, Yu. V. Gulyaev, S. G. Chigarev, E. A. Vilkov, E. M. Epshtein, and Gennady M. Mikhailov
- Subjects
Physics ,Magnetization ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Ferromagnetism ,Solid-state physics ,Terahertz radiation ,Precession ,Antiferromagnetism ,Resonance ,Condensed Matter::Strongly Correlated Electrons ,Magnetic field - Abstract
Spin-polarized current can tilt magnetic sublattices in an antiferromagnetic layer of a ferromagnet-antiferromagnet junction without imposing any external magnetic field. Thus, the current can induce magnetization in the antiferromagnetic layer. This effect seemingly took place in experiments on the observation of terahertz emission at the precession frequencies of current-induced magnetization. In this work, the mechanisms of motion of the induced magnetization, as well as the possibility of detection and generation of radiation emitted during such motion, are suggested and discussed. The notion of spin-injection antiferromagnetic resonance is introduced.
- Published
- 2013
29. Terahertz emission in the ferromagnetic-antiferromagnetic structure
- Author
-
Yu. V. Gulayev, P. E. Zilberman, S. I. Kasatkin, S. G. Chigarev, and Gennady M. Mikhailov
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Terahertz radiation ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Hardened steel ,Magnetization ,Ferromagnetism ,Precession ,Antiferromagnetism ,Electrical and Electronic Engineering ,Current (fluid) ,Layer (electronics) - Abstract
Current flow in the structure consisting of a hard-magnetic ferromagnetic rod (hardened steel) with a diameter of up to 100 μm that contacts a thin (10–100 nm) ferromagnetic (FeMn) film is studied at room temperature. Effective magnetization is induced in the FeMn film in the presence of the spin-polarized current in spite of the absence of the intrinsic magnetization. The terahertz radiation that is detected in this work is caused by the precession of the induced magnetization. The emission is interpreted using the recent theoretical predictions on the effect of the sd exchange on the lattice dynamics of antiferromagnetic layer.
- Published
- 2013
30. Analysis of the frequency characteristics of the spin-injection emitter in the terahertz range using a diffraction grating
- Author
-
Gennady M. Mikhailov, I. V. Malikov, and S. G. Chigarev
- Subjects
Diffraction ,Radiation ,Materials science ,Terahertz radiation ,business.industry ,Physics::Optics ,Condensed Matter Physics ,Signal ,Electronic, Optical and Magnetic Materials ,Optics ,Ferromagnetism ,Thermal ,Electrical and Electronic Engineering ,business ,Diffraction grating ,Common emitter - Abstract
A method for the measurement and identification of the radiation frequencies of the spin-injection oscillator in the terahertz frequency range using a diffraction grating is developed and experimentally implemented. For the system consisting of a ferromagnetic rod (Fe) and nanosized ferromagnetic film (Fe3O4 with a thickness of up to 100 nm), the thermal and dynamic components of the radiation that is induced by the current flow are separated. The diffraction peaks at a frequency of about 9.6 THz and a band of 37% at a level of 3 dB and at a frequency of 43.5 THz are demonstrated. It is shown that the intensity of each signal is significantly higher than the thermal background level.
- Published
- 2013
31. Current-induced resonance in ferromagnet-antiferromagnet junctions
- Author
-
E. M. Epshtein, Gennady M. Mikhailov, S. G. Chigarev, P. E. Zilberman, Yu. V. Gulyaev, and V. D. Kotov
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Terahertz radiation ,Detector ,Resonance ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Nuclear magnetic resonance ,Ferromagnetism ,Condensed Matter::Superconductivity ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Current (fluid) ,Current density - Abstract
The response of a ferromagnet-antiferromagnet junction to a high-frequency magnetic field is calculated as a function of the spin-polarized current density through the junction. Conditions are chosen under which the response is zero in absence of such a current. It is shown that increasing in the current density leads to proportional increase in the resonance frequency and resonant absorption. A principal possibility is indicated of using ferromagnet-antiferromagnet junction as a terahertz radiation detector.
- Published
- 2012
32. Spin-Injection Terahertz Radiation in Magnetic Junctions
- Author
-
A. I. Panas, S. G. Chigarev, I. V. Malikov, Gennady M. Mikhailov, P. E. Zilberman, Yu. V. Gulyaev, and E. M. Epshtein
- Subjects
Physics ,education.field_of_study ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Spin polarization ,Orders of magnitude (temperature) ,Terahertz radiation ,Population ,Condensed Matter Physics ,Electromagnetic radiation ,Atomic and Molecular Physics, and Optics ,Ferromagnetism ,General Materials Science ,Electric current ,Joule heating ,education ,Spin-½ - Abstract
Electromagnetic radiation of 1 - 10 THz range is observed at room temperature in a structure with a point contact between a ferromagnetic rod and a thin ferromagnetic film under electric current of high enough density. The radiation is due to nonequilibrium spin injection between the components of the structure. By estimates, the injection can lead to inverted population of the spin subbands. The radiation power exceeds by orders of magnitude the thermal background (with the Joule heating taking into account) and follows the current without inertia. Efficiency of the oscillator depends strongly on the material used and quantum efficiency may exceed the unity. It means the stimulated radiation processes play an important role.
- Published
- 2012
33. Observation of the spin-injection terahertz emission in planar ferromagnetic two-layer structures
- Author
-
S. G. Chigarev, E. M. Epshtein, I. V. Malikov, Gennady M. Mikhailov, P. E. Zilberman, and Yu. V. Gulyaev
- Subjects
Range (particle radiation) ,education.field_of_study ,Radiation ,Materials science ,Condensed matter physics ,Terahertz radiation ,Population ,Non-equilibrium thermodynamics ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Planar ,chemistry ,Ferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Spin (physics) ,education ,Magnetite - Abstract
The spin-injection emission of the system that consists of a nonmagnetic conducting rod and two-layer planar heteroepitaxial structure formed by thin metal and magnetite films is experimentally studied. The electromagnetic emission in the terahertz range is demonstrated for the first time due to the creation of the nonequilibrium population of the spin energy subbands (relatively low current densities of about 105 A/cm2 are needed at room temperature).
- Published
- 2012
34. Efficiency of the terahertz spin-injection emitter
- Author
-
P. E. Zilberman, Yu. V. Gulyaev, S. G. Chigarev, E. M. Epshtein, Gennady M. Mikhailov, and I. V. Malikov
- Subjects
Range (particle radiation) ,Radiation ,Materials science ,business.industry ,Terahertz radiation ,Quantum yield ,Condensed Matter Physics ,Concentrator ,Magnetic flux ,Electronic, Optical and Magnetic Materials ,Optics ,Ferromagnetism ,Radiative transfer ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Common emitter - Abstract
The energy efficiency of the spin-injection emitter based on the rod-film ferromagnetic structure with a point contact between the components in the terahertz frequency range is experimentally estimated. The film material substantially affects the efficiency. A concentrator of magnetic flux is proposed for an increase in the efficiency. The experimental estimations allow the quantum yield of the emitter that is greater than unity. This result indicates significant contribution of the stimulated radiative transitions.
- Published
- 2011
35. Exchange switching of a magnetic junction by a current pulse
- Author
-
P. E. Zilberman, Yu. V. Gulyaev, E. M. Epshtein, and S. G. Chigarev
- Subjects
Phase transition ,Radiation ,Materials science ,Condensed matter physics ,Computer simulation ,Exchange interaction ,Field strength ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Orientation (geometry) ,Electrical and Electronic Engineering ,Magnetic reactance ,Current density - Abstract
Results of numerical simulation of switching of a magnetic transition induced by a spin-polarized current pulse in the presence of an external magnetic field for a current density and a field strength that are lower than the corresponding threshold values are presented. The magnetic field regenerates the system and drives it to the threshold of an orientation phase transition, which simplifies exchange switching induced by a current pulse. This switching is characterized by the same locality as the exchange interaction, i.e., it is local at atomic lengths. It is demonstrated that there exists the possibility of switching with a controllable delay with respect to the current pulse.
- Published
- 2011
36. Current induced exchange switching of magnetic junctions with cubic anisotropy of a free layer
- Author
-
P. E. Zilberman, Yu. V. Gulyaev, E. M. Epshtein, and S. G. Chigarev
- Subjects
Threshold current ,Materials science ,Solid-state physics ,Computer simulation ,Condensed matter physics ,Plane (geometry) ,Current (fluid) ,Condensed Matter Physics ,Anisotropy ,Stability (probability) ,Layer (electronics) ,Electronic, Optical and Magnetic Materials - Abstract
The stability of equilibrium configurations of magnetic junctions with a free layer of cubic anisotropy with two axes in the layer plane has been analyzed. Variants of switching between different configurations have been considered. It has been demonstrated that the possibility exists of considerably decreasing the threshold current density necessary for switching. Numerical simulation of the dynamics of switching between different configurations has been performed.
- Published
- 2011
37. Spin-injection terahertz radiation in bilayer epitaxial magnetic planar nanostructures
- Author
-
S. G. Chigarev, I. V. Malikov, E. M. Epstein, P. E. Zilberman, and Gennady M. Mikhailov
- Subjects
Materials science ,Spins ,business.industry ,Terahertz radiation ,Bilayer ,Physics::Optics ,General Physics and Astronomy ,Population inversion ,Condensed Matter::Materials Science ,Wavelength ,Planar ,Ferromagnetism ,Optoelectronics ,Current (fluid) ,business - Abstract
The generation of electromagnetic THz waves by a current is experimentally investigated in planar structures comprised of two ferromagnetic films. When the films come into contact with a thin copper rod, the current is applied to both layers. The first layer, which plays the role of an injector, polarizes the spins of the current carriers. In the second working layer, the conditions are created for spin population inversion and the generation of THz waves. At a current of 350 mA, the radiation wavelength is 16.4 THz and a power of 10 mW is reached at room temperature.
- Published
- 2014
38. Spin Polarized Current in Magnetic Nanojunctions
- Author
-
P. E. Zilberman, S. G. Chigarev, Yurii V Gulyaev, and E. M. Epshtein
- Subjects
Phase transition ,Magnetization ,Materials science ,Condensed matter physics ,Spin polarization ,Spin wave ,Spinplasmonics ,Spin Hall effect ,Spin valve ,General Materials Science ,Giant magnetoresistance ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics - Abstract
Two channels of the s-d exchange interaction are considered in magnetic junctions. The first channel describes the interaction of transversal spins with the lattice magnetization. The second channel describes the interaction of longitudinal spins with the magnetization. We show that the longitudinal channel leads to a number of significant effects: 1) drastic lowering of the current-instability threshold down to three (or even more) orders of magnitude; 2) creation of sufficiently large distortion of equilibrium due to the current- driven spin injection leading to inversion of populations of the energy spin subbands and laser-like instability in the THz frequency range at room temperature. External magnetic field is likely to tend to additionally lower the instability threshold due to the proximity effect of purely magnetic reorientation phase transition. This effect demonstrates new properties: the giant magnetoresistance (GMR) becomes strongly current-dependent and the exchange switching becomes of very low threshold. We derived some matching condition that should be satisfied to achieve high spin injection level. Some characteristic quantities appeared in the condition, namely, the so called "spin resistances" , where the a number of a layer in the junction. For a three-layer junction ( ), the matching condition is , where the number corresponds to the main functional layer. We investigated also the junctions having variable lateral dimensions of the layers, for example, a ferromagnetic rod contacting with a very thin ferromagnetic film. A large enhancement of the current density can appear near the contact region, leading to the spin injection luminescence.
- Published
- 2010
39. Spin-polarized current in a rod-to-film structure
- Author
-
E. M. Epshtein, Yu. V. Gulayev, S. G. Chigarev, and P. E. Zilberman
- Subjects
education.field_of_study ,Radiation ,Materials science ,Condensed matter physics ,Terahertz radiation ,Population ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Film structure ,Ferromagnetism ,Thermal ,Electrical and Electronic Engineering ,education ,High current density ,Radiant intensity - Abstract
Properties are discussed of a ferromagnetic junction in the form of a rod contacting with a film. Very high current density of the order of j ∼ 109 A/cm2 may be achieved in the contact region that can lead to inversion of population of the spin energy subbands. The inversion depends strongly on the direction of the current (forward or backward). We prepared experimentally a rod-to-film structure and investigated high density current flowing through it. Current dependent radiation has been observed by means of a THz receiver, the radiation intensity being different for forward and backward currents. It shows that the radiation includes not only thermal contribution but also non-thermal (spin-injection) one.
- Published
- 2010
40. Current-induced spin injection from probe to ferromagnetic film
- Author
-
A. I. Panas, P. E. Zilberman, Yu. V. Gulyaev, S. G. Chigarev, and E. M. Epshtein
- Subjects
Radiation ,Materials science ,Condensed matter physics ,Spin polarization ,Zero field splitting ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Ferromagnetism ,Spin wave ,Spin diffusion ,Spin Hall effect ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Quantum spin liquid ,Spin-½ - Abstract
The distribution of the spin polarization of conduction electrons is calculated under the conditions for the spin injection from a probe to a ferromagnetic film in the presence of current. It is demonstrated that the main parameters that determine the deviation of the spin polarization from equilibrium are the current density and spin polarization of the probe material, whereas the ratio of the probe diameter to the spin diffusion length weakly affects the result in certain ranges. The population inversion of the spin subbands can be reached at distances of about spin diffusion length from the probe-film interface.
- Published
- 2010
41. Anisotropic magnetoresistance of the epitaxial single-crystal Fe(001) film of nanoscale thickness
- Author
-
Gennady M. Mikhailov, I. V. Malikov, L. A. Fomin, E. M. Epshtein, P. E. Zilberman, and S. G. Chigarev
- Subjects
Radiation ,Materials science ,Field (physics) ,Magnetoresistance ,Condensed matter physics ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Condensed Matter::Materials Science ,Magnetic anisotropy ,Paramagnetism ,Hysteresis ,Electrical and Electronic Engineering ,Anisotropy ,Single crystal - Abstract
The dependence of the anisotropic magnetoresistance (AMS) of the single-crystal Fe(001) film grown with the aid of the pulsed laser evaporation on the direction and magnitude of the external magnetic field is analyzed. Three ranges of magnetic fields with different types of variation in AMS with the direction of magnetic field are revealed. The discontinuities of resistance and the hysteresis are demonstrated in a certain range of magnetic fields. The anisotropy field is estimated using the experimental results.
- Published
- 2010
42. Lower current-driven exchange switching threshold in noncollinear magnetic junctions under high spin injection
- Author
-
P. E. Zilberman, E. M. Epshtein, and S. G. Chigarev
- Subjects
Work (thermodynamics) ,Materials science ,Ferromagnetism ,Condensed matter physics ,Condensed Matter::Superconductivity ,Magnetization reversal ,Current (fluid) ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Spin injection ,Electronic, Optical and Magnetic Materials - Abstract
Current-induced switching is considered in a magnetic junction. The junction includes pinned and free ferromagnetic layers which work in the regime of the high spin injection. It is shown that in such a regime the exchange magnetization reversal threshold can be lowered up to two times when the axes of the layers are noncollinear.
- Published
- 2009
43. Current in a system formed by a microprobe and a thin-film layered structure
- Author
-
A. I. Krikunov, E. M. Epshtein, A. I. Panas, P. E. Zilberman, and S. G. Chigarev
- Subjects
Microprobe ,Radiation ,Materials science ,Current distribution ,Flow (psychology) ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,Layered structure ,Operation mode ,Electrical and Electronic Engineering ,Current (fluid) ,Thin film ,Current density - Abstract
The current in a system formed by a conducting microprobe and a thin-film layered structure is experimentally studied. The possibility of a stable current flow with a density of up to 3 × 106 A/cm2 is demonstrated. It is found that, in order to attain an operation mode with a high current density, a sufficiently strong current (∼200 mA) must be first transmitted through the sample. The current distribution in the studied structure is calculated. The theoretical distribution is found to be in agreement with experimental results.
- Published
- 2009
44. Ferromagnetic nanojunctions at a high current-induced spin injection
- Author
-
A. I. Krikunov, A. I. Panas, P. E. Zilberman, Yu. V. Gulyaev, E. M. Epshtein, and S. G. Chigarev
- Subjects
Phase transition ,Radiation ,Materials science ,Spin polarization ,Spins ,Condensed matter physics ,Orders of magnitude (temperature) ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Magnetization ,Ferromagnetism ,Electrical and Electronic Engineering ,Spin-½ - Abstract
A perpendicular current that flows through a ferromagnetic nanojunction (a layered nanosized spinvalve structure containing two ferromagnetic metal layers separated by a spacer) is studied. The spacer is thick enough to prevent the exchange coupling of the layers in the absence of the current. On the other hand, the spacer is sufficiently thin and does not affect the spin polarization in the presence of the current. Conditions for a relatively high current-induced spin injection are found. Under such conditions, the concentration of the injected nonequilibrium spins can be equal to or even greater than the equilibrium concentration and several new effects are observed: The threshold of the exchange switching by the current decreases by several orders of magnitude owing to the matching of the spin resistances of the layers, the threshold additionally decreases in the presence of an external magnetic field in the vicinity of the orientational phase transition, and multistability emerges (several stable noncollinear orientations of magnetization correspond to a single value of the current). Switching appears to be irreversible.
- Published
- 2008
45. Tunnel Magnetoresistance of Fe3O4/MgO/Fe Nanostructures
- Author
-
E. M. Epshtein, I. V. Malikov, Gennady M. Mikhailov, P. E. Zilberman, and S. G. Chigarev
- Subjects
Magnetization ,Magnetic anisotropy ,Paramagnetism ,Tunnel magnetoresistance ,Nanostructure ,Materials science ,Magnetic energy ,Condensed matter physics ,Condensed Matter::Superconductivity ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Anisotropy ,Magnetic field - Abstract
A magnetic tunnel junction Fe3O4/MgO/Fe with (001) layer orientation is considered. The junction magnetic energy is analyzed as a function of the angle between the layer magnetization vectors under various magnetic fields. The tunnel magnetoresistance is calculated as a function of the external magnetic field. In contrast with junctions with unidirectional anisotropy, a substantially lower magnetic field is required for the junction switching.
- Published
- 2011
46. Magnetic junction switching by joint action of current pulse and magnetic field: numerical simulation
- Author
-
S. G. Chigarev, E. M. Epshtein, P. E. Zilberman, and Yu. V. Gulyaev
- Subjects
Physics ,Physics and Astronomy (miscellaneous) ,Magnetic energy ,Electromagnet ,Magnetic reluctance ,Magnetostatics ,Computational physics ,law.invention ,Magnetic circuit ,Nuclear magnetic resonance ,law ,Magnetic pressure ,Magnetic reactance ,Magnetic dipole - Abstract
The process of magnetic junction switching by a spin-polarized current pulse in the presence of an external magnetic field has been numerically simulated at the current densities and magnetic fields below the corresponding threshold values for separate effects. It is established that the switching can be performed with controlled delay relative to the current pulse.
- Published
- 2011
47. Spin injection-driven switching in a magnetic junction
- Author
-
S. G. Chigarev, E. M. Epshtein, A. I. Krikunov, P. E. Zilberman, Yu. V. Gulyaev, and A. I. Panas
- Subjects
Materials science ,Ferromagnetism ,Spin polarization ,Condensed matter physics ,Magnetic structure ,Spin-transfer torque ,Spin valve ,Spinplasmonics ,Spin Hall effect ,Condensed Matter::Strongly Correlated Electrons ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Spin-½ - Abstract
We investigate a perpendicular electric current passing through a “ferromagnetic nanojunction”, that is through some layered nanosized structure of spin-valve type, containing two ferromagnetic metallic layers. Spacer may be used between the metallic layers to prevent the rotation of the moving spin phases. Such an arrangement is typical for spin valves: one of the metallic layers has strongly pinned magnetic lattice and the other one has free magnetic lattice and free mobile spins. Further the conditions are derived to provide a very high nonequilibrium spin injection level. It appears that the so-called spin resistances of the constitutive layers should be in definite relations to each other. These relations lead to the situation where the spin injection becomes dominant and significantly suppresses the “ordinary” spin-transfer torque. As a result, the threshold current becomes lowered down to 2–3 and even more orders of magnitude.
- Published
- 2009
48. Tunnel magnetoresistance of magnetic junctions with cubic symmetry of the layers
- Author
-
S. G. Chigarev, P. E. Zilberman, and E. M. Epshtein
- Subjects
Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Demagnetizing field ,Spin valve ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Condensed Matter Physics ,Magnetic hysteresis ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Magnetic susceptibility ,Electronic, Optical and Magnetic Materials ,Paramagnetism ,Tunnel magnetoresistance ,Magnetic anisotropy ,Magnetization ,Condensed Matter::Superconductivity - Abstract
A tunnel magnetic junction is considered with magnetic hard and magnetic soft layers of cubic symmetry. The magnetic switching is analyzed of the layers by a magnetic field perpendicular to the initial magnetizations. In such a situation, an additional peak of the TMR ratio appears at the magnetic field value lower substantially than the anisotropy energy of the soft layer., Comment: 7 pages, 3 figures
- Published
- 2009
- Full Text
- View/download PDF
49. Operation of the Short-Millimeter-Wave Orotron on the Second Space Harmonic
- Author
-
S. G. Chigarev, V. V. Evdokimov, A. Ilyin, and E. A. Myasin
- Subjects
Physics ,Optics ,business.industry ,Terahertz radiation ,Harmonics ,Extremely high frequency ,Harmonic ,Physics::Optics ,Optoelectronics ,Millimeter ,business ,Space (mathematics) ,Wavelength band - Abstract
The possibility of terahertz generation in orotron operating on high-order space harmonics is considered. Experimental results for orotron operation on the second space harmonic in short-wave part of millimeter wavelength band are presented.
- Published
- 2006
50. Experimental study of 2 MM orotron
- Author
-
V. V. Evdokimov, S. G. Chigarev, E. A. Myasin, and A.Y. IIyin
- Subjects
Optics ,Materials science ,business.industry ,Electrical engineering ,business ,Voltage - Abstract
The experimental study of orotron tuning in 90 - 145 GHz frequency range is carried out for accelerating voltages up to 20 kV. Two period values of two-row periodic structures and three values of inter-row spacing have been investigated as well.
- Published
- 2005
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.