Книжкові видання та компакт-диски Журнали та продовжувані видання Автореферати дисертацій Реферативна база даних Наукова періодика України Тематичний навігатор Авторитетний файл імен осіб
|
Для швидкої роботи та реалізації всіх функціональних можливостей пошукової системи використовуйте браузер "Mozilla Firefox" |
|
|
Повнотекстовий пошук
Пошуковий запит: (<.>A=Grechnev A$<.>) |
Загальна кількість знайдених документів : 6
Представлено документи з 1 до 6
|
1. |
Freiman Yu. A. Sound velocities in solid hydrogen under pressure [Електронний ресурс] / Yu. A. Freiman, A. Grechnev, S. M. Tretyak, A. F. Goncharov, R. J. Hemley // Физика низких температур. - 2013. - Т. 39, № 5. - С. 548-551. - Режим доступу: http://nbuv.gov.ua/UJRN/PhNT_2013_39_5_7 We present results of semi-empirical lattice dynamics calculations of the sound velocities in solid hydrogen under pressure based on the many-body intermolecular potential and first-principle density-functional theory (DFT). Both the sound velocities and elastic moduli are in excellent agreement with data from Brillouin scattering measurements while Silvera - Goldman and Hemley - Silvera - Goldman potentials tend to overestimate the sound velocity. It is shown that the stiffer is the potential the greater is overestimated the sound velocity. As was the case for equation of state and Raman-active lattice phonon calculations, the employed many-body potential works well for phases I and II (up to ~ 140 GPa while for higher pressures the use of the DFT is preferable.
| 2. |
Freiman Yu. A. Poisson’s ratio in cryocrystals under pressure [Електронний ресурс] / Yu. A. Freiman, A. Grechnev, S. M. Tretyak, A. F. Goncharov, E. Gregoryanz // Физика низких температур. - 2015. - Т. 41, № 6. - С. 571-575. - Режим доступу: http://nbuv.gov.ua/UJRN/PhNT_2015_41_6_10
| 3. |
Freiman Yu. A. Quantum rotors in Pca21 lattice [Електронний ресурс] / Yu. A. Freiman, A. Grechnev // Физика низких температур. - 2016. - Т. 42, № 6. - С. 655-659. - Режим доступу: http://nbuv.gov.ua/UJRN/PhNT_2016_42_6_14
| 4. |
Grechnev G. E. Electronic structure and properties of novel layered superconductors [Електронний ресурс] / G. E. Grechnev, A. V. Logosha, A. A. Lyogenkaya, A. G. Grechnev, A. V. Fedorchenko // Ukrainian journal of physics. - 2014. - Vol. 59, № 3. - С. 284-291. - Режим доступу: http://nbuv.gov.ua/UJRN/Ukjourph_2014_59_3_16 The electronic energy structures and magnetic properties of layered superconductors RNi2B2C, RFe4Al8, and FeSe are systematically studied, by using the density functional theory (DFT). The calculations allowed us to reveal a number of features of the electronic structure, which can cause the manifestation of peculiar structural, magnetic and superconducting properties of these systems. It is demonstrated that the Fermi energy EF is located close to the pronounced peaks of the electronic density of states (DOS). The main contribution to DOS at the Fermi level arises from 3d-electrons. The calculations of the pressure-dependent electronic structure and the magnetic susceptibility in the normal state indicate that the novel superconductors are very close to a magnetic instability with dominating spin paramagnetism. It is shown that experimental data on the pressure dependence of the superconducting transition temperature in FeSe correlate qualitatively with the calculated behavior of DOS at EF as a function of the pressure.
| 5. |
Grechnev G. E. Electronic structure and properties of novel layered superconductors [Електронний ресурс] / G. E. Grechnev, A. V. Logosha, A. A. Lyogenkaya, A. G. Grechnev, A. V. Fedorchenko // Український фізичний журнал. - 2014. - Т. 59, № 3. - С. 286-293. - Режим доступу: http://nbuv.gov.ua/UJRN/UPhJ_2014_59_3_16 The electronic energy structures and magnetic properties of layered superconductors RNi2B2C, RFe4Al8, and FeSe are systematically studied, by using the density functional theory (DFT). The calculations allowed us to reveal a number of features of the electronic structure, which can cause the manifestation of peculiar structural, magnetic and superconducting properties of these systems. It is demonstrated that the Fermi energy EF is located close to the pronounced peaks of the electronic density of states (DOS). The main contribution to DOS at the Fermi level arises from 3d-electrons. The calculations of the pressure-dependent electronic structure and the magnetic susceptibility in the normal state indicate that the novel superconductors are very close to a magnetic instability with dominating spin paramagnetism. It is shown that experimental data on the pressure dependence of the superconducting transition temperature in FeSe correlate qualitatively with the calculated behavior of DOS at EF as a function of the pressure.
| 6. |
Grechnev A. G. Influence of magnetic anisotropy on hysteresis behavior in the two-spin model of a ferro/antiferromagnet bilayer with exchange bias [Електронний ресурс] / A. G. Grechnev, A. S. Kovalev, M. L. Pankratova // Физика низких температур. - 2012. - Т. 38, № 10. - С. 1184-1190. - Режим доступу: http://nbuv.gov.ua/UJRN/PhNT_2012_38_10_7 The influence of magnetic anisotropy of ferromagnetic film on the phenomenon of exchange bias is studied. Hysteresis behavior in the two-spin model of a ferro/antiferromagnet (FM/AFM) bilayer with exchange bias has been investigated in detail. In this model a half-space of AFM with fixed magnetic configuration contacts with a two-layer FM film. Twelve different types of magnetization curves M(H) (both with and without hysteresis) have been found. Some of the M(H) curves demonstrate unusual features, such as plateaus and inclined segments. The hysteresis loop becomes asymmetric if the surface anisotropy is taken into account.
|
|
|