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| 3. |
- Fisun, V. V., et al.
(författare)
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Features in nonlinear electroconductivity of nanocontacts on the base of ferromagnetic metals (Co and Fe)
- 2004
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Ingår i: Metallofizika i novejsie tehnologii. - 1024-1809. ; 26:11, s. 1439-1446
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Tidskriftsartikel (refereegranskat)abstract
- For normal metal-ferromagnet (N-F) point contacts, a step-like change of the resistance is observed at reaching of the current density similar to 10(9) A/cm(2). This is observed only for the case, when electron flow is directed from the normal metal to the ferromagnetic one, and is connected with magnetization reversal in the microconstriction at high transport-current density. Increasing of a magnetic field leads to the shift of observed peculiarity into the higher-current region that testifies its magnetic origin. As shown, the observed effect, which is widely studied in the recent time in N-F sandwiches, has more common character and requires the presence only N-F boundary and high-current density. The increasing of the amplitude of the resistance peculiarity is observed at electromagnetic radiation with a frequency of 3.10(9) Hz that testifies stimulating influence of the HF-radiation on the dynamics of precessing spins in the contacts at issue.
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| 5. |
- Khansili, Akash, et al.
(författare)
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Calorimetric measurement of nuclear spin-lattice relaxation rate in metals
- 2023
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 107:19
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Tidskriftsartikel (refereegranskat)abstract
- The quasiparticle density of states in correlated and quantum-critical metals directly probes the effect of electronic correlations on the Fermi surface. Measurements of the nuclear spin-lattice relaxation rate provide one such experimental probe of quasiparticle mass through the electronic density of states. By far the most common way of accessing the spin-lattice relaxation rate is via nuclear magnetic resonance and nuclear quadrupole resonance experiments, which require resonant excitation of nuclear spin transitions. Here we report nonresonant access to spin-lattice relaxation dynamics in AC-calorimetric measurements. The nuclear spin-lattice relaxation rate is inferred in our measurements from its effect on the frequency dispersion of the thermal response of the calorimeter-sample assembly. We use fast, lithographically defined nanocalorimeters to access the nuclear spin-lattice relaxation times in metallic indium from 0.3 to 7 K and in magnetic fields up to 35 T.
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| 6. |
- Korenivski, Vladislav, et al.
(författare)
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Stimulated emission of radiation using spin-population inversion in metals
- 2013
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Ingår i: Proceedings - 2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves, MSMW 2013. - : IEEE. - 9781479910663 ; , s. 259-261
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Konferensbidrag (refereegranskat)abstract
- The discovery of masers and lasers has led to major breakthroughs in science and technology. Later important developments include compact semiconductor lasers for visible to near-infrared and quantum-cascade lasers for far-infrared to THz radiation.
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| 7. |
- Naidyuk, Yu G., et al.
(författare)
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Magnetic unipolar features in conductivity of point contacts between normal and ferromagnetic D-metals (Co, Ni, Fe)
- 2007
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Ingår i: Electron Correlation in New Materials and Nanosystems. - 9781402056574 ; , s. 59-69
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Konferensbidrag (refereegranskat)abstract
- In nanocontacts between normal and ferromagnetic metals (N-F) abrupt changes of the order of 1 % are detected in differential resistance, dV/dI(V), versus bias voltage, V, on achieving of high current densities, 10(9) A/cm(2). These features in dV/dI(V) are observed when the electron flow is directed from the nonmagnetic metal into the ferromagnet and connected with magnetization excitations in the ferromagnet induced by the current. Applying an external magnetic field leads to a shift of the observed features to higher biasing current, confirming the magnetic nature of the effect. Such effects are observed for the non-ballistic (not spectral) regime of current flow in the nanocontacts. Thus, the current induced magneto-conductance effects in multilayered N-F structures (nanopillars) extensively studied in the recent literature have much more general character and can be stimulated by elastic electron scattering at single N-F interfaces.
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| 9. |
- Sarkar, K., et al.
(författare)
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Effects of magnetic fields on the Datta-Das spin field-effect transistor
- 2020
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Ingår i: Physical Review B. - 2469-9950. ; 102:11
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Tidskriftsartikel (refereegranskat)abstract
- A Datta-Das spin field-effect transistor is built of a heterostructure with a Rashba spin-orbit interaction (SOI) at the interface (or quantum well) separating two possibly magnetized reservoirs. The particle and spin currents between the two reservoirs are driven by chemical potentials that are (possibly) different for each spin direction. These currents are also tuned by varying the strength of the SOI, which changes the amount of the rotation of the spins of electrons crossing the heterostructure. Here we investigate the dependence of these currents on additional Zeeman fields on the heterostructure and on variations of the reservoir magnetizations. In contrast to the particle current, the spin currents are not necessarily conserved; an additional spin polarization is injected into the reservoirs. If a reservoir has a finite (equilibrium) magnetization, then we surprisingly find that the spin current into that reservoir can only have spins which are parallel to the reservoir magnetization, independent of all the other fields. This spin current can be enhanced by increasing the magnetization of the other reservoir, and can also be tuned by the SOI and the various magnetic fields. When only one reservoir is magnetized then the spin current into the other reservoir has arbitrary tunable size and direction. In particular, this spin current changes as the magnetization of the other reservoir is rotated. The optimal conditions for accumulating spin polarization on an unpolarized reservoir are to either apply a Zeeman field in addition to the SOI, or to polarize the other reservoir.
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| 10. |
- Shekhter, R. I., et al.
(författare)
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Microcavity Terahertz spin-flip laser proposal
- 2011
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Ingår i: Int. Conf.Transparent Opt. Networks. - 9781457708800
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Konferensbidrag (refereegranskat)abstract
- We present a novel design for a single-mode, truly sub-wavelength THz disk laser based on a nano-composite gain medium comprising an array of metal or ferromagnetic point contacts embedded in a thin dielectric layer. Stimulated emission of light occurs due to spin-flip relaxation of spin-polarized electrons injected from the ferromagnetic side of the contacts. Ultra-high electrical current densities in the contacts and a dielectric material with a large refractive index, neither condition being achievable in conventional semiconductor media, allows the thresholds of lasing to be overcome for the lowest-order modes of the disk, hence making single-mode operation possible.
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