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Wyszukujesz frazę "72.20.Pa" wg kryterium: Temat


Wyświetlanie 1-16 z 16
Tytuł:
Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te Crystals as a New Thermoelectric Material
Autorzy:
Osinniy, V.
Jędrzejczak, A.
Domuchowski, W.
Dybko, K.
Witkowska, B.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2044514.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
72.80.Jc
Opis:
We studied experimentally thermoelectric properties of p-type bulk crystals of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te and Pb$\text{}_{1-x-y}$Ag$\text{}_{y}$Mn$\text{}_{x}$Te (0≤ x≤ 0.083 and y≤0.017) at room and liquid nitrogen temperatures. Model calculations of the thermoelectric figure of merit parameter (Z) involved the analysis of carrier concentration, carrier mobility, density of states as well as electronic and lattice contributions to the thermal conductivity of PbMnTe. In the analysis we took into account the main effect of Mn concentration on the band structure parameters of PbMnTe, i.e. the increase of the energy gap. The analysis of electrical, thermoelectric, and thermal properties of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te crystals showed that, at room temperature, the maximum values of the parameter Z occur in crystals with Mn content 0.05≤ x≤0.07 and are comparable with a maximal value of Z observed in PbTe. At T=400 K the increase in the parameter Z by 10% is expected in Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te crystal (as compared to PbTe) for a very high concentration of holes of about p=5×10$\text{}^{19}$ cm$\text{}^{-3}$. The experimental data correctly reproduce the theoretical Z(p) dependence.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 809-816
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Transport Properties of $Yb_{8-x}Y_xV_2O_{17}$ (x=0,2,8)
Autorzy:
Sawicki, B.
Piz, M.
Filipek, E.
Groń, T.
Duda, H.
Powiązania:
https://bibliotekanauki.pl/articles/1398346.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
72.80.Ga
75.20.-g
Opis:
The UV-vis-NIR and electrical properties of $Yb_{8-x}Y_xV_2O_{17}$ for x=0, 2, and 8 were investigated. The band energy gap of 2.6 eV determined for $Yb_6Y_2V_2O_{17}$ (x=2) and comparable for the remaining compounds with x=0 and 8 is characteristic for insulators. Low electrical conductivity with a characteristic minimum shifting to higher temperatures from 322, via 360 to 370 K in the sequence x=0, 2 and 8, which decreases with increasing content of ytterbium was observed. Temperature dependence of thermoelectric power showed n-p transition at 410 and 467 K for x=0 and 2, respectively, and n-type conductivity for x=8, indicating mainly n-type electrical conductivity. A breakdown voltage of 26 V/mm is mainly observed for the I-V characteristics at 400 K and showing a varistor-like behavior.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 363-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Cr-Substitution on the Electrical Properties of $Fe_{1-x}Cr_xVSbO_6$
Autorzy:
Duda, H.
Filipek, E.
Dąbrowska, G.
Groń, T.
Mydlarz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1399099.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
72.80.Ga
75.20.-g
Opis:
$Fe_{1-x}Cr_xVSbO_6$ solid solution is semiconductor with the activation energy decreasing both in the intrinsic and extrinsic conductivity temperature regions as the Cr-content increases. The n-type conduction is observed for Fe-richer samples while a change of the Seebeck coefficient (from n to p) - for Cr-richer ones. Magnetic isotherms for all samples of solid solution under study are characteristic of the universal Brillouin function, indicating paramagnetic response. These effects are discussed within the framework of the appearance of the mixed valence of both Fe and Cr ions.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 833-835
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Cr-Substitution on the Electrical Properties of $Fe_{1-x}Cr_{x}SnSbO_6$
Autorzy:
Groń, T.
Dąbrowska, G.
Filipek, E.
Duda, H.
Sawicki, B.
Powiązania:
https://bibliotekanauki.pl/articles/1398554.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
72.80.Ga
75.20.-g
Opis:
$Fe_{1-x}Cr_xSnSbO_6$ solid solution shows semiconducting behaviour with the activation energy decreasing from $E_{A}$=0.64 eV for x=0.0 to $E_{A}$=0.32 eV for x=1.0 in the intrinsic conductivity temperature region as well as the n-type conduction at room temperature. The I-V characteristics and the conductance G at 300 and 400 K showed symmetrical and nonlinear behavior in the voltage range (-100, 100 V) suggesting the electron emission over the potential barrier especially for the boundary compounds FeSnSbO₆ and CrSnSbO₆. These effects are discussed in the context of the energy gap $E_{g}$>1.6 eV many times greater than the thermal energy kT.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-153-A-156
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Properties of Sr₂InV₃O₁₁
Autorzy:
Groń, T.
Filipek, E.
Pacześna, A.
Urbanowicz, P.
Sawicki, B.
Duda, H.
Powiązania:
https://bibliotekanauki.pl/articles/1398582.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
72.80.Ga
75.20.-g
Opis:
The electrical conductivity σ (T) and thermoelectric power S(T) measurements of Sr₂InV₃O₁₁ showed the insulating state and the change of sign of thermopower from p to n at $T_{n-p}$=400 K. The I-V characteristics provided the evidence of symmetrical and non-linear behaviour typical of strong emission of charge carriers induced by temperature and voltage. Relative dielectric permittivity $ε_{r}$ as well as loss tangent (tan δ) strongly depend both on the temperature in the range of 295-400 K and the frequency in the range of 5×10² to 1×10⁶ Hz, showing the broad maximum at 320 K. These effects are considered as a relaxation process like in the Maxwell-Wagner or Jonscher model as well as the conduction of electric current, as determined by the Joule-Lenz law.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1239-1241
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Transport Properties of RNiSb Compounds (R = Gd, Tb, Dy, Yb, Lu)
Autorzy:
Skolozdra, R. V.
Guzik, A.
Goryn, A. M.
Pierre, J.
Powiązania:
https://bibliotekanauki.pl/articles/1964639.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Mb
72.15.Eb
72.20.Pa
Opis:
The structural, magnetic, electrical and thermoelectric properties of heavy rare-earths ternary compounds RNiSb were investigated. Except Yb-based compound (and nonmagnetic Lu), all compounds are low temperature antiferromagnets. YbNi$\text{}_{0.9}$Sb reflects some mixed valence behaviour. Magnitude of the resistivity indicates that investigated compounds are semimetals or high doped semiconductors.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 343-346
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Properties of $CeCu_4Ag$ Compound
Autorzy:
Kowalczyk, A.
Toliński, T.
Falkowski, M.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1534756.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.80.-g
72.15.Cz
72.20.Pa
Opis:
The magnetic and electronic properties including electrical resistivity, thermal conductivity and thermopower are discussed for the heavy fermion $CeCu_4Ag$ compound. The electrical resistivity shows a Kondo-like logarithmic increase up to a maximum at T = 75 K. Thermopower is positive over the whole temperature range and below $T_\text{max}$ = 25 K falls rapidly. The measured thermal conductivity of the $CeCu_4Ag$ compound increases with increasing temperature.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 936-937
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Power of $CeNi_4Si$ and $YbNi_4Si$ Compounds
Autorzy:
Falkowski, M.
Kowalczyk, A.
Tran, V.
Miiller, W.
Powiązania:
https://bibliotekanauki.pl/articles/1813661.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
72.20.Pa
71.28.+d
Opis:
The thermoelectric power was measured from 4.2 to 300 K for $CeNi_4Si$ and $YbNi_4Si$. The thermoelectric power was analysed in the framework of the phenomenological resonance model. According to the model the dominant contribution to thermopower is caused by scattering between electrons of a broad s-band and a narrow f-band with the Lorentzian shape. The electron-hole analogy is reflected in the thermoelectric power behaviour of the investigated compounds.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 303-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconducting Properties of $Cu_5SbO_6$
Autorzy:
Groń, T.
Filipek, E.
Dąbrowska, G.
Duda, H.
Mazur, S.
Kukuła, Z.
Pawlus, S.
Powiązania:
https://bibliotekanauki.pl/articles/1409627.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
72.20.Pa
75.50.Gg
Opis:
Thermoelectric power, electrical resistivity, I-V characteristics, relative electrical permittivity, dc magnetization and ac magnetic susceptibility measurements carried out on $Cu_5SbO_6$ showed p-type semiconducting behaviour with the activation energy of 0.24 eV as well as ferrimagnetic order with the Néel temperature of 5.2 K. The effective magnetic moment of 5.857 $μ_{B}$/f.u. revealed the orbital contribution to the magnetic moment. Large value of the relative electrical permittivity indicated that the $Cu^{2+}$ ions with the unscreened and unfilled electron shells are responsible for the polarizability and forming of electric dipoles.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1105-1107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Effects in Planar Tunnel Junctions
Autorzy:
Wilczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1427569.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
73.40.Gk
73.40.Rw
Opis:
The thermopower and the charge current generated by the finite temperature gradient applied to ferromagnetic planar tunnel junctions are investigated in the spin-polarized free-electron-like one-band model. It has been shown that the current depends almost linearly on the temperature difference between the electrodes while the thermopower does not depend significantly on the temperature gradient. The studied quantities depend on the magnetic configuration of the junction. The form of this dependence is sensitive to the height of the barrier, but is not sensitive to the temperature difference between the electrodes.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1188-1190
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnon Drag Effect on Resistivity and Thermoelectric Power of Semimetallic Antiferromagnet USb
Autorzy:
Henkie, Z.
Wiśniewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1943936.pdf
Data publikacji:
1995-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Eb
72.20.Pa
75.50.Ee
72.15.Jf
Opis:
Resistivity ρ(T) and absolute thermoelectric power S(Τ) have been measured for USb single crystals characterized by different residual resistivity ratios, RRR = ρ(300 K)/ρ(4.2 K). A 50 μV/K peak of S(Τ) observed at 40 K for high RRR crystal vanishes for low RRR one. The ρ ∝ Τ$\text{}^{4}$ dependence observed below 40 K changes to the ρ ∝ Τ $\text{}^{5}\text{}^{/}\text{}^{2}$ one. These variations are ascribed to reduction of the magnon drag effect by an increased incoherent magnetic scattering of carriers, possibly induced by a small change of composition. Resistivity anomaly is analysed above the antiferromagnetic transition temperature T$\text{}_{N}$. We have found that resistivity decreases as tlnt in the range 0.02 ≤ t ≤ 0.35, where t = (Τ - T$\text{}_{N}$)/T$\text{}_{N}$. It is ascribed to a semimetallic character of this compound.
Źródło:
Acta Physica Polonica A; 1995, 88, 6; 1103-1112
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seebeck Coefficient and Optical Studies of Cadmium Doped $CuInS_{2}$ Single Crystal
Autorzy:
Chaki, S.
Powiązania:
https://bibliotekanauki.pl/articles/1807787.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
72.20.Pa
78.20.-e
61.50.-f
Opis:
Single crystals of $CuInS_{2}$ were successfully grown by chemical vapor transport technique using iodine as transporting agent. The as-grown chemical vapor transport $CuInS_{2}$ single crystals were found to have large resistivity. To decrease the resistivity of the crystals they were doped with three different cadmium concentrations. Seebeck coefficient variation with temperature is measured for all the three doped samples. Optical bandgaps were determined for these three doped samples using optical absorption spectra. The obtained results are discussed in detail.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 221-225
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Seebeck Effect in Double Tunnel Junctions with Ferromagnetic Electrodes and Central Layer Separated by Nonmagnetic Barriers
Autorzy:
Wilczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030503.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Pa
73.40.Gk
73.40.Ty
73.50.Lw
Opis:
The Seebeck effect is analysed in the double planar tunnel junctions consisting of ferromagnetic electrodes and the central layer separated by nonmagnetic barriers with the arbitrary angle between magnetic moments in neighbouring ferromagnetic layers. The Seebeck coefficient is calculated as a function of the thickness of the central layer. The influence of temperature of the junction and the relative orientation of magnetic moments in ferromagnetic layers on this coefficient is also analysed. Calculations are performed in the linear response theory using the free-electron model. It has been found that the Seebeck coefficient oscillates with the thickness of the central layer and can be strongly enhanced in the junction with special central layer thickness due to electron tunnelling by resonant states. The form of the observed oscillations depends on the temperature of the junction. The magnitude of the Seebeck coefficient usually increases with the increase of the angle between magnetic moments in the neighbouring ferromagnetic layers as in the case of single junctions. However, in the junctions with the specially designated central layer the decrease of the magnitude of the Seebeck coefficient with the increase of this angle can be observed.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 544-547
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Pressure Treatment up to 25~GPa of Czochralski Grown Si Samples Containing Different Admixtures and Defects
Autorzy:
Shchennikov, V.
Shchennikov, Vs.
Korobeynikov, I.
Morozova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1399450.pdf
Data publikacji:
2013-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uf
81.40.Vw
72.20.Pa
62.50.-p
05.70.Fh
Opis:
The thermoelectric properties of a set of single crystalline Si wafers with different oxygen concentration grown by the Czochralski technique have been studied at ultrahigh pressures up to 25 GPa. The dependence of semiconductor-metal transition pressure at Czochralski grown Si on the concentration $c_{O}$ of the interstitial oxygen was found to present a convex curve with the maximum near $c_{O} \approx 9 \times 10^{17} cm^{-3}$. The high pressure thermoelectric power method seems to be suitable for characterization of impurity-defect structure of Si wafers. For $Si_{1 - x}Ge_{x}$ crystals (1% < x < 3%) the strong changes of both the value and the sign of thermoelectric power have been observed at pressures much less than ones of Si-I → Si-II transition. From nanoindentation data the phase transition Si-I → Si-II, corresponding to semiconductor-metal electronic transformation has been detected at the loading up to ≈ 10 mN. These findings suggest a way for creation of integrated circuits, in which zones with different types of conductivity and hence different p-n, p-n-p etc. structures may be "written" by applied stress at nanoscale level, and the control on the value of the above stresses now is possible by the proposed nanoindentation technique.
Źródło:
Acta Physica Polonica A; 2013, 124, 2; 244-249
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanostructure features, phase relationships and thermoelectric properties of melt-spun and spark-plasma-sintered skutterudites
Autorzy:
Kogut, Iu.
Nichkalo, S.
Ohorodniichuk, V.
Dauscher, A.
Candolfi, C.
Masschelein, P.
Jacquot, A.
Lenoir, B.
Powiązania:
https://bibliotekanauki.pl/articles/1052685.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Eb
72.15.Jf
72.20.Pa
66.70.Df
81.20.Ev
81.16.-c
81.40.Gh
Opis:
Reduction of thermal conductivity remains a main approach relevant to enhancement of figure-of-merit of most thermoelectric materials. Melt spinning combined with spark plasma sintering appears to be a vital route towards fine-grain skutterudites with improved thermoelectric performance. However, upon high-temperature processing the Fe_{4-x}Co_{x}Sb_{12}-based skutterudites are prone to decompose into multiple phases, which deteriorate their thermoelectric performance. In this study we addressed the effects of combined melt spinning and spark plasma sintering on the phase composition and microstructural properties of filled Fe_{4-x}Co_{x}Sb_{12} as well as their influence on thermoelectric characteristics of these compounds. The crystallites of filled Fe_{4-x}Co_{x}Sb_{12} were effectively reduced to sizes below 100 nm upon melt spinning, but also severe decomposition with weakly preserved nominal phase was observed. Spark plasma sintering of melt spun skutterudites resulted in even further reduction of crystallites. Upon short annealing and sintering the n-type materials easily restored into single-phase filled CoSb₃ with nanoscale features preserved, while secondary phases of FeSb₂ and Sb remained in p-type compounds. Relatively high figure-of-merit ZT_{max} of 0.9 at T ≈ 400°C has been gained in nanostructured Yb_{x}Co₄Sb_{12}, however, no significant reduction of thermal conductivity was observed. Abundant impurities in p-type filled Fe_{4-x}Co_{x}Sb_{12} led to drastic drop in their ZT, which even further degraded upon thermal cycling.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 879-883
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence and Photoacoustic Investigations of Beryllium and Magnesium Containing Wide Gap II-VI Mixed Crystals
Autorzy:
Firszt, F.
Łęgowski, S.
Męczyńska, H.
Sekulska, B.
Szatkowski, J.
Zakrzewski, J.
Paszkowicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/2010957.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.30.Pa
62.65.+k
72.20.My
78.20.Hp
78.55.Et
Opis:
Zn$\text{}_{1-x}$Be$\text{}_{x}$Se, Cd$\text{}_{1-x}$Mg$\text{}_{x}$Se and Zn$\text{}_{1-x-y}$Be$\text{}_{x}$Mg$\text{}_{y}$Se mixed crystals grown from the melt with different concentrations of Be and Mg have been characterized by photoluminescence and photoacoustic methods. An increase in band gap energy with increasing Be and Mg contents was observed. The photoacoustic spectroscopy was also employed for evaluation of thermal diffusivity of mixed Zn$\text{}_{1-x}$Be$\text{}_{x}$Se crystals with different beryllium contents.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 991-996
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-16 z 16

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