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Wyszukujesz frazę "Flachbart, K." wg kryterium: Autor


Tytuł:
Superconductivity in $Lu_xZr_{1-x}B_{12}$ Dodecaborides with Cage-Glass Crystal Structure
Autorzy:
Sluchanko, N.
Azarevich, A.
Bogach, A.
Gavrilkin, S.
Glushkov, V.
Demishev, S.
Mitsen, K.
Shitsevalova, N.
Filippov, V.
Gabani, S.
Flachbart, K.
Powiązania:
https://bibliotekanauki.pl/articles/1398292.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.-q
74.62.Bf
74.70.Ad
Opis:
We probed the evolution of the superconducting transition temperature $T_c$ and the normal state parameters of $Lu_xZr_{1-x}B_{12}$ solid solutions employing resistivity, heat capacity and magnetization measurements. In these studies of high-quality single crystals it was found that there are two types of samples with different magnetic characteristics. An unusually strong suppression of superconductivity in $Lu_xZr_{1-x}B_{12}$ with a rate $dT_c/dx=0.21 K/at.%$ of Lu was observed previously on the first "magnetic" set of crystals, and it was argued to be caused by the emergence of static spin polarization in the vicinity of non-magnetic lutetium ions. On the contrary, the second (current) set of "nonmagnetic" crystals demonstrates a conventional $T_c(x)$ dependence with a rate $dT_c/dx=0.12 K/at.%$ of Lu which is typical for BCS-type superconductors doped by nonmagnetic impurities. The reason for this difference is yet unclear. Moreover, the H-T phase diagram of the superconducting state of $Lu_xZr_{1-x}B_{12}$ (0 ≤ x ≤ 1) solid solutions has been deduced from magnetization measurements.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1036-1038
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Point-Contact Spectroscopy of Crystalline Electric Field of Heterocontacts $PrB_6$ and $NdB_6$ with Pt
Autorzy:
Vasil'ová, M.
Pristáš, G.
Reiffers, M.
Flachbart, K.
Rusz, J.
Shitsevalova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1813641.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Np
71.70.Ch
74.50.+r
Opis:
Point-contact spectra of single crystals $PrB_6$ and $NdB_6$ are presented. We observed maxima connected with crystalline electric field excitations in agreement with previous results for applied voltage V>8 mV. Moreover, we observed maxima at 6 mV $(PrB_6)$ and 3 mV $(NdB_6)$, which are probably connected with phonon modes. Moreover, we observed phonon peak at 10.6 mV in $PrB_6$. Further measurements in magnetic fields and crystalline electric field calculations are necessary.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 267-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Drag and Magnetic Anomalies of Thermopower in $RB_{12}$ (R = Ho, Er, Tm, Lu)
Autorzy:
Glushkov, V.
Demishev, S.
Ignatov, M.
Khayrullin, E.
Sluchanko, N.
Shitsevalov, N.
Levchenko, A.
Filipov, V.
Flachbart, K.
Siemensmeyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1813647.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Jf
75.50.Ee
Opis:
High precision measurements of the Seebeck coefficient S(T) were carried out on the single crystals of $RB_{12}$ (R = Ho, Er, Tm, Lu) at temperatures 2-300 K. It was shown that the effects of phonon drag result from vibrations of rare earth ions ($ħω_E$≈10-33 meV) in the rigid framework structure of the $B_{12}$ clusters and determine the main contribution to thermopower at intermediate temperatures (30-300 K). The correlated behavior of transport parameters favors the appreciable enhancement of spin fluctuations in the sequence of magnetic compounds $(HoB_{12}-TmB_{12})$ when approaching to the valence instability state in $YbB_{12}$. The giant increase in S(T) detected in the vicinity of the Néel temperature $T_N$ for $HoB_{12},$ $ErB_{12},$ and $TmB_{12}$ seems to result from the density of states renormalization caused by antiferromagnetic ordering.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 275-278
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Diagram of $TmB_4$ Probed by AC Calorimetry
Autorzy:
Kačmarčík, J.
Pribulová, Z.
Gabáni, S.
Samuely, P.
Siemensmeyer, K.
Shitsevalova, N.
Flachbart, K.
Powiązania:
https://bibliotekanauki.pl/articles/1534368.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.50.Ee
Opis:
TmB_4 is a frustrated system based on the Shastry-Sutherland lattice that exhibits complex magnetic properties. In this contribution the magnetic field B vs. temperature T phase diagram of $TmB_4$ has been studied by ultrasensitive AC calorimetry in the temperature range between 2.9 and 12 K and in magnetic fields up to 8 T. Apart from already known phases our measurements have recognized several new phase transitions suggesting that the phase diagram of $TmB_4$ is even more complex and deserves further studies.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 903-904
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructural Analysis and Transport Properties of $RuO_2$-Based Thick Film Resistors
Autorzy:
Gabáni, S.
Flachbart, K.
Pavlík, V.
Pietriková, A.
Gabániová, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813961.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.40.Xx
72.80.-r
73.40.Rw
Opis:
$RuO_2$-based low temperature sensors appear as very good secondary thermometers, mainly in the temperature range below 4.2 K. This is due to their high temperature sensitivity and small magnetoresistance. Both properties are strongly influenced by the manufacturing process (mainly by firing temperature and firing time). In our contribution we show that the microstructure of sensors and the temperature dependence of their resistance R(T) down to 50 mK, in case when all sensors are prepared from the same paste, can be strongly influenced by change of the firing temperature from 800°C to 900°C. The paper also presents results on the X-ray microanalysis and the analysis of electrical conductivity of these sensors.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 625-628
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoresistance Anisotropy and Magnetic H-T Phase Diagram of $Tm_{0.996}Yb_{0.004}B_{12}$
Autorzy:
Sluchanko, N.
Azarevich, A.
Bogach, A.
Glushkov, V.
Demishev, S.
Gavrilkin, S.
Gabani, S.
Flachbart, K.
Shitsevalova, N.
Filipov, V.
Vanacken, J.
Moshchalkov, V.
Stankiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1371466.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Gd
73.43.Qt
75.30.Kz
75.20.Hr
75.50.Ee
Opis:
The antiferromagnetic ground state has been studied by transverse magnetoresistance, heat capacity and magnetization measurements, which were carried out on high quality single crystals of $Tm_{0.996}Yb_{0.004}B_{12}$ dodecaboride in strong magnetic fields at liquid helium temperatures. Both antiferromagnetic-paramagnetic (AF-P) and spin-orientation (AF1-AF2) phase transitions have been observed, and allowed to construct a complicated magnetic H-T phase diagram for this compound. Strong magnetoresistance anisotropy was found both in AF states (ρ(H||[110])/ρ(H||[111])~ 1.2 at H~ 20 kOe) and at the critical field of AF-P transition $(H_{N}[100]$/$H_{N}[111]$~ 1.25) in this magnetic metal with a simple fcc crystal structure.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 332-333
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetocaloric Effect in Geometrically Frustrated Magnetic Compound $HoB_{12}$
Autorzy:
Snyman, J.
Flachbart, K.
Gabani, S.
Reiffers, M.
Shitsevalova, N.
Siemensmeyer, K.
Strydom, A.
Powiązania:
https://bibliotekanauki.pl/articles/1534216.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Sg
75.40.Cx
Opis:
The magnetocaloric effect of frustrated antiferromagnetic $HoB_{12}$ is calculated. The isothermal entropy change Δ S characterising the magnetocaloric effect shows a small positive change upon magnetisation below the transition temperature $T_{N}$, indicating a small inverse magnetocaloric effect. At $T_{N}$, Δ S shows clear scaling behaviour with the applied magnetic field. The adiabatic temperature change Δ T shows paramagnetic behaviour above $T_{N}$, despite strong magnetic correlations that persist in this temperature region. The adiabatic temperature change calculated for $HoB_{12}$ is appreciable.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 873-874
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Structure and Phase Diagram of $TmB_4$
Autorzy:
Gabáni, S.
Maťaš, S.
Priputen, P.
Flachbart, K.
Siemensmeyer, K.
Wulf, E.
Evdokimova, A.
Shitsevalova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1813619.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.25.+z
Opis:
Magnetic structure of single crystalline $TmB_4$ has been studied by magnetization, magnetoresistivity, and specific heat measurements. A complex phase diagram with different antiferromagnetic phases was observed below $T_{N1}$=11.7 K. Besides the plateau at half-saturated magnetization (1/2 $M_S$), also plateaus at 1/9, 1/8 and 1/7 of $M_S$ were observed as a function of applied magnetic field Bparallel c. From additional neutron scattering experiments on $TmB_4$, we suppose that these plateaus arise from a stripe structure which appears to be coherent domain boundaries between antiferromagnetic-ordered blocks of 7 or 9 lattice constants. The received results suggest that the frustration among the $Tm^{3+}$ magnetic ions, which maps to a geometrically frustrated Shastry-Sutherland lattice, leads to a strong competition between antiferromagnetic and ferromagnetic order. Thus, stripe structures in intermediate field appear to be the best way to minimize the magnetostatic energy against other magnetic interactions among the Tm ions combined with very strong Ising anisotropy.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 227-230
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Phase Diagram of $TmB_{4}$ under High Pressure
Autorzy:
Gabáni, S.
Pristáš, G.
Takáčová, I.
Flachbart, K.
Filipov, V.
Shitsevalova, N.
Siemensmeyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1371562.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.25.+z
74.25.F
62.50.-p
Opis:
$TmB_{4}$ is a Shastry-Sutherland frustrated system which exhibits very complex magnetic properties. In this contribution the phase diagram of magnetic field vs. temperature of $TmB_{4}$ under hydrostatic pressure up to 26.5 kbar is investigated using sensitive ac-resistance measurements. Temperature and magnetic field dependences of resistance at various pressures were carried out in a piston cylinder pressure cell between 1.7 and 14 K and in magnetic fields up to 6 T. The obtained results exhibit shifts of ordering temperatures $T_{N}$ as well as shifts of boundaries between different magnetic phases. The observed pressure dependences of $T_{N}$ can be described by the relation d $lnT_{N}$/dp=+(0.16÷0.18) %/kbar. The effect of pressure on various interactions between magnetic ions in this compound is discussed.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 356-357
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Ordering in Boron-Rich Borides $TbB_{66}$ and $GdB_{66}$
Autorzy:
Flachbart, K.
Gabani, S.
Mori, T.
Siemensmeyer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1534232.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Ck
75.30.Cr
77.84.Bw
78.70.Nx
Opis:
Magnetic ordering in $TbB_{66}$ and $GdB_{66}$ was investigated at very low temperatures. Measurements of ac susceptibility have shown rather clear features of magnetic ordering below 1 K, at 0.34 K for $TbB_{66}$ and at 0.20 K for $GdB_{66}$. However, no clear evidence of long range magnetic order was found by neutron scattering experiments. Reasons leading to these observations are discussed.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 875-876
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Field Influence on the Thermal Conductivity of $PrB_6$
Autorzy:
Priputen, P.
Reiffers, M.
Gabáni, S.
Flachbart, K.
Šantavá, E.
Šebek, J.
Alekseev, P.
Nefeodova, E.
Sadikov, I.
Shitsevalova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1813706.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.60.-k
72.15.Eb
Opis:
Results of thermal conductivity measurements on single crystalline $PrB_6$ sample in the temperature range of 2-30 K and in magnetic field up to 14 T are presented. The obtained results are discussed in order to estimate the electron, phonon, and magnetic contributions to thermal conductivity. Taking into account the results of electrical resistivity of this compound the temperature dependence of the reduced Lorentz function is determined.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 383-386
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Field Enhancement of the Hall Effect in Dilute Magnetic System $La_{1 - x}Ce_{x}B_6$ (x ≤ 0.1)
Autorzy:
Bogach, A.
Glushkov, V.
Demishev, S.
Sluchanko, N.
Shitsevalova, N.
Fillipov, V.
Flachbart, K.
Powiązania:
https://bibliotekanauki.pl/articles/1534686.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Gd
Opis:
Magnetic field dependences of the Hall coefficient $R_{H}$ and resistivity have been studied in detail for dilute magnetic compounds $La_{1-x}Ce_{x}B_6$ (x ≤ 0.1) at temperatures 1.8-300 K. It was established that the regime of weak localization of charge carriers, which was observed in these heavy fermion systems below 30 K destroys gradually in magnetic field up to 8 T. Moreover, in addition to the strong negative magnetoresistance (Δρ/ρ ≈ 80%) a drastic enhancement of the negative Hall coefficient in magnetic field (Δ $R_{H}//R_{H}$ ≈ 50%) has been deduced at liquid helium temperatures. The results of comprehensive analysis contradict the predictions of Kondo-impurity approach for this archetypal strongly correlated electron system in the dilute impurity limit. An alternative interpretation of $La_{1-x}Ce_{x}B_6$ properties is developed on the basis of spin-polaron approach, Pauli paramagnetism and the density of states renormalization effects at low temperatures.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 931-932
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Transport and Magnetic Properties of SmB$\text{}_{6}$
Autorzy:
Gabani, S.
Flachbart, K.
Pavlík, V.
Konovalova, E.
Paderno, Y.
Herrmannsdörfer, T.
Powiązania:
https://bibliotekanauki.pl/articles/2013029.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.Hr
71.28.+d
Opis:
We present results of transport and magnetic properties of three single-crystalline samples of the intermediate valence small-gap semiconductor SmB$\text{}_{6}$ at low temperatures. The received resistivity dependences of the samples below 0.5 K exhibit an activated behavior with an energy gap of a few mK. The temperature dependences of the magnetic susceptibility show an increase below 15 K which can be accounted for by impurities, by bare Sm$\text{}^{3+}$ ions or by a small amount of in-gap magnetic 4f$\text{}^{5}$5d$\text{}^{1}$ states.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 419-422
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Mixed Valence State of $Sm_{1-x}B_{6}$ and $Sm_{1-x}La_{x}B_{6}$ by XANES
Autorzy:
Gabáni, S.
Flachbart, K.
Bednarčík, J.
Welter, E.
Filipov, V.
Shitsevalova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1371509.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
71.28.+d
71.27.+a
Opis:
We investigated the valence states of samarium ions in Sm deficient $Sm_{1-x}B_{6}$ (x=0.03, 0.05, 0.08, 0.1 and 0.2) sintered samples, in single crystalline solid solutions $Sm_{1-x}La_{x}B_{6}$ (x=0.16, 0.28, 0.4, 0.55 and 0.7) as well as in a $SmB_{6}$ single crystal by X-ray absorption near edge structure (XANES) between 4.2 and 300 K. It was shown that the mixed valence state $v_{Sm}$ of Sm-ions ($v_{Sm}$ ≈ 2.51 for $SmB_{6}$ at 4.2 K) in deficient samples is changed but maintained up to a concentration of 20% of vacancies and up to a concentration of 70% in samples doped with trivalent La-ions, and that in both cases it increases with temperature. On the other hand, the value of $v_{Sm}$ increases with increasing vacancy level, whereas it decreases with increasing $La^{3+}$ substitution. The obtained dependences of Sm-valence in $SmB_{6}$ on vacancy as well as on $La^{3+}$ ion concentration are in good agreement with susceptibility measurements and exact numerical calculation of the spinless Falicov-Kimball model in two dimensions.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 338-339
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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