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Wyszukujesz frazę "Anisimov, M.V." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Reentrant Metal-Insulator Transition in $Ca_{1-x}Eu_{x}B_{6}$
Autorzy:
Glushkov, V.
Anisimov, M.
Baybakov, R.
Demishev, S.
Filippov, V.
Flachbart, K.
Kuznetsov, A.
Shitsevalova, N.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1369362.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
72.15.Gd
75.47.Gk
Opis:
Resistivity, Hall and Seebeck effects have been studied on single crystals of $Ca_{1-x}Eu_{x}B_{6}$ (0 ≤ x ≤ 1) at temperatures 2-300 K and in magnetic fields up to 8 T. An insulating ground state is found to be limited by narrow range of Eu doping 0.6 ≤ x ≤ 0.8. This region is characterized by an enhanced colossal magnetoresistance (CMR), which reaches values of ρ(0)/ρ(7T) > $10^{6}$ for x = 0.63 at T < 10 K. Decreasing of Eu content in $Ca_{1-x}Eu_{x}B_{6}$ below x* ≈ 0.6 restores the metallic ground state with moderate resistivity (ρ ~ 1 ÷ 5 mΩ·cm) and CMR amplitude (ρ(0)/ρ(7T) < 7). The second metal-insulator transition (MIT) in $Ca_{1-x}Eu_{x}B_{6}$ is observed beyond the whole conductivity region found earlier in the narrow range of Eu doping (0.7 ≤ x ≤ 0.8). The correlation between the enhanced CMR amplitude, the onset of positive diffusive thermopower and the elevation of anomalous Hall effect, determined for Eu content 0.6 ≤ x ≤ 0.85, favors the idea that a smooth change of band structure is the main factor governing the reentrant MIT in $Ca_{1-x}Eu_{x}B_{6}$.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 294-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Transport and Magnetism in $Eu_{1-x}Ca_{x}B_6$
Autorzy:
Glushkov, V.
Anisimov, M.
Batko, I.
Batkova, M.
Bogach, A.
Demishev, S.
Filipov, V.
Flachbart, K.
Kuznetsov, A.
Sannikov, I.
Shitsevalova, N.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1534292.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.30.+h
75.30.Cr
75.40.-s
75.47.Gk
Opis:
Transport, magnetic and thermal properties of substitutional solid solution $Eu_{1 - x}Ca_{x}B_6$ single crystals (0 ≤ x ≤ 0.244) have been studied at 1.8 ≤ T ≤ 300 K and in magnetic fields up to 8 T. Calcium doping is shown to result in a metal-insulator transition, which occurs at x_{MIT} ≈ 0.2. In vicinity of metal-insulator transition the effect of colossal magnetoresistance is found to be very sensitive to Ca content, the amplitude varying from Δ = [ ρ (0)- ρ (8T)]/ρ(8T) ≈1.4 × $10^2$ to Δ ≈ 7.5 × $10^3$ for 0.14 ≤ x ≤ 0.16. The analysis of magnetic contribution to heat capacity shows that a large amount of magnetic entropy ( ≈ 30%) releases in $Eu_{0.845}Ca_{0.155}B_6$ when moving from the Curie temperature $T_{C}$ ≈ 5.5 K to the characteristic one T* ≈ 30 K. This observation as well as the large amplitude of low field colossal magnetoresistance effect and the deviation of magnetic susceptibility from the Curie-Weiss law detected for x = 0.155 compound in the interval $T_{C}$ ≤ T ≤ T* seem to be associated with magnetic phase separation induced by Ca doping.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 891-892
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hall Effect in $GdB_{6}$
Autorzy:
Anisimov, M.
Bogach, A.
Glushkov, V.
Demishev, S.
Samarin, N.
Shitsevalova, N.
Levchenko, A.
Filippov, V.
Kuznetsov, A.
Flachbart, K.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1371548.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Gd
Opis:
The Hall effect of $GdB_{6}$ has been studied on high quality single crystals in the temperature range 2-150 K and in magnetic field of 1 T. The obtained data allow to detect anomalies in the antiferromagnetic (AF) phase including (i) a drastic enhancement of negative Hall coefficient below $T_{N1}$ ≈ 15.5 K and (ii) the appearance of an anomalous Hall effect at $T_{N2}$ ≈ 4.7 K. Possible scenarios of the AF ground state formation are discussed.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 348-349
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of Magnetoresistance in HoB₁₂
Autorzy:
Khoroshilov, A.
Krasnorussky, V.
Bogach, A.
Glushkov, V.
Demishev, S.
Levchenko, A.
Shitsevalova, N.
Filipov, V.
Gabáni, S.
Flachbart, K.
Anisimov, M.
Siemensmeyer, K.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1032153.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
Opis:
We present results of precision measurements of magnetoresistance of isotopically pure Ho¹¹B₁₂ at low temperatures 2÷10 K in magnetic field up to 80 kOe of different orientation to the crystal axes. The data obtained revealed strong anisotropy of magnetoresistance and allowed us to reconstruct magnetic H-T phase diagrams for main crystallographic directions H || [001], [110], and [111]. Analysis of magnetoresistance derivatives allowed to conclude in favor of two main magnetoresistance contributions. Among of them the negative quadratic component is attributed to charge carriers scattering on a magnetic clusters of Ho³⁺ ions (4f component) and positive linear one may be explained in terms of scattering on a spin density waves (5d component).
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 976-978
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of the charge transport in GdB₆
Autorzy:
Anisimov, M.
Glushkov, V.
Bogach, A.
Demishev, S.
Samarin, N.
Samarin, A.
Shitsevalova, N.
Levchenko, A.
Filipov, V.
Gábani, S.
Flachbart, K.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1052920.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Gd
Opis:
The anisotropy of charge transport was investigated in the antiferromagnetic II state of GdB₆ from precise measurements of transverse magnetoresistance. Based on the data obtained we detected a complicated behavior of magnetoresistance curves which are characterized by the appearance of considerable hysteresis on the field and angular dependences below T_{N2}. Moreover it was shown that the system GdB₆ is sensitive to cooling-warming prehistory. The data analysis allowed to reconstruct magnetic H-T phase diagram of GdB₆ along main crystallographic directions (H||⟨001⟩,⟨110⟩,⟨111⟩) and to propose additional phase transition inside AF II phase at H₁ ≈ 0.5 T.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 973-975
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Transport and Magnetism in $Tm_{0.03}Yb_{0.97}B_{12}$
Autorzy:
Glushkov, V.
Azarevich, A.
Anisimov, M.
Bogach, A.
Demishev, S.
Dukhnenko, A.
Filipov, V.
Flachbart, K.
Gabáni, S.
Gavrilkin, S.
Kondrin, M.
Shitsevalova, N.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1398286.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Gd
72.15.Jf
71.27.+a
Opis:
Transport and magnetic properties of polycrystalline $Tm_{0.03}Yb_{0.97}B_{12}$ samples were investigated at temperatures 1.8-300 K in magnetic fields up to 9 T. The activated behavior of resistivity, the Hall coefficient and thermopower is described in terms of a narrow gap $ε_g$ ≈ 16.6 meV, which controls the charge transport in $Tm_{0.03}Yb_{0.97}B_{12}$ at T>40 K. The maximum of magnetic susceptibility found at 50 K is shown to be induced by a spin gap Δ ≈ 4.7 meV being close to the half of the spin fluctuation energy in YbB₁₂. Large diffusive thermopower S=AT, A=-29.1 μV/K² and the Pauli susceptibility χ₀ ≈ 7.2×10¯³ emu/mol found below 20 K seem to be associated with the many-body resonance, which corresponds to states with an enhanced effective mass m* ≈ 250m₀ (m₀ - free electron mass). The effective parameters of magnetic centers and the analysis of anomalies favor the nonequivalent states of substitute Tm ions.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 985-987
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect Mode in $LaB_{6}$
Autorzy:
Anisimov, M.
Bogach, A.
Glushkov, V.
Demishev, S.
Samarin, N.
Gavrilkin, S.
Mitsen, K.
Shitsevalova, N.
Levchenko, A.
Filippov, V.
Gabani, S.
Flachbart, K.
Sluchanko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1371551.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.Ba
Opis:
The specific heat of high quality $La^{N}B_{6}$ (N=10, 11, natural) single crystals is investigated in a wide range of temperatures 2 - 300 K. The obtained data allow to estimate correctly (i) the electronic γ· T term of specific heat (γ ≈ 2.4 mJ/(mol·$K^{2}$)), (ii) the contribution from quasilocal vibrating mode of $La^{3+}$ ions ($Θ_{E}$ ≈ 150 - 152 K), (iii) the Debye-type term from rigid boron cages ($Θ_{D}$ ≈ 1160± 40 K). Our data also suggest an additional defect-mode component (iv) which may be attributed to a contribution of 1.5% boron vacancies in $LaB_{6}$. The obtained results may be interpreted in terms of formation of two level systems, which appear when $La^{3+}$ ions are displaced from their centrosymmetric positions in the cavities of rigid boron cages, apart from randomly distributed boron vacancies in the $LaB_{6}$ matrix.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 350-351
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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