Temat: 75.47.Gk - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Barrier and Self-Energy Effects in Manganite Tunneling Characteristics
Autorzy:: Svistunov, V.
Revenko, Y.
Belogolovskii, M.
Gerasimenko, A.
Pashkevich, Y.
Szymczak, H.
Przyslupski, P.
Komissarov, I.
Tematy:: 75.47.Gk
75.47.Lx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2037099.pdf Link otwiera się w nowym oknie
Opis:: Tunneling conductance spectra of point-contact junctions formed by a sharp Ag tip and two optimally doped manganites La$\text{}_{0.67}$Sr$\text{}_{0.33}$MnO$\text{}_{3}$ and Nd$\text{}_{0.67}$ Sr$\text{}_{0.33}$MnO$\text{}_{3}$ are measured and analyzed. It was found that the analytical dependence of the differential conductance on voltage strongly depends on the bias sign and dramatically changes after voltage treatments. The data obtained are explained in terms of the Glasman-Matveev model for tunneling across two localized states settled in the barrier near the manganite bulk. Effective functions of electron-boson interaction extracted from self-energy contributions to the experimental characteristics contain signs of phonon and magnon excitations, higher-energy satellites as a result of possible orbital ordering and a hallmark of localized states in the near-barrier region in the form of strong not-well reproduced peaks.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Elastic Properties of Double-Layered Manganite $La_{1.2}Sr_{1.8-x}Ba_xMn_2O_7$ (x=0.0-0.4)
Autorzy:: Reddy, Y.
Prashanth Kumar, V.
Ramesh, S.
Venkanna, S.
Ramana Reddy, M.
Kistaiah, P.
Vishnuvardhan Reddy, C.
Tematy:: 75.47.Gk
75.47.Lx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1812358.pdf Link otwiera się w nowym oknie
Opis:: The elastic behavior of the sol-gel prepared double-layered manganite system $La_{1.2}Sr_{1.8-x}Ba_xMn_2O_7$ (x = 0.0-0.4) was investigated at 300 K, employing ultrasonic pulse transmission technique at 1 MHz. The values of elastic moduli and acoustic Debye temperature $(θ_D)$ were computed from longitudinal and shear velocities. The measured values were corrected to zero porosity using Hasselman and Fulrath's formula. The elastic constants of the samples, estimated using Modi's heterogeneous metal-mixture rule, were also reported. The variation of elastic moduli with Ba concentration was interpreted in terms of strength of interatomic bonding.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: HPM Generation by Tri-Anode Coaxial Vircator
Autorzy:: Shao, H.
Liu, G.
Zhang, Y.
Yang, Z.
Sun, J.
Tematy:: 75.47.Gk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1807906.pdf Link otwiera się w nowym oknie
Opis:: A novel type of coaxial vircator with 3 anodes is proposed. The advantages on high power microwave generation is tested by particle-in-cell simulation and theoretical analysis model is set up as well. The tri-anode coaxial vircator behaves a very stable frequency in the pulse duration. In the tri-anode coaxial vircator, the injecting electron beam is well premodulated in the first anode cavity and forms an inerratic bunch-dispersion mechanism in the second anode cavity; the energy-loss electrons penetrate through the third anode and absorbed by the dumping cavity locates in the centre electrode, which helps keeping the bunch-dispersion cycle undisturbed. A 3.8 GHz tri-anode coaxial vircator is theoretically designed and optimized by particle-in-cell simulation, which gives beam-wave conversion efficiency of over 20% with a stable predominant frequency, in accordance with the particle-in-cell simulation and analytic model.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A $\text{}^{55}$Mn NMR Study of La$\text{}_{0.33}$Nd$\text{}_{0.33}$Ca$\text{}_{0.34}$Mn O$\text{}_{3}$ with $\text{}^{16}$O and $\text{}^{18}$O
Autorzy:: Rybicki, D.
Kapusta, Cz.
Riedi, P. C.
Oates, C. J.
Sikora, M.
Zając, D.
De Teresa, J. M.
Marquina, C.
Ibarra, M. R.
Tematy:: 76.60.-k
75.47.Gk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2037128.pdf Link otwiera się w nowym oknie
Opis:: A $\text{}^{55}$Mn NMR study of $\text{}^{16}$O and $\text{}^{18}$O containing La$\text{}_{0.33}$Nd$\text{}_{0.33}$Ca$\text{}_{0.34}$Mn O$\text{}_{3}$ is reported. The spin-echo spectra measured at 4.2 K and zero field consist of a double exchange line corresponding to the ferromagnetic metallic regions. The line intensity is more than an order of magnitude lower for the $\text{}^{18}$O compound, which indicates an order of magnitude lower content of the ferromagnetic metallic phase in this compound. The frequency dependence of the spin-spin relaxation time T$\text{}_{2}$ shows a pronounced minimum at the center of the double exchange line of both compounds due to the Suhl-Nakamura interaction, which indicates that the ferromagnetic metallic regions are at least 10~nm in size. The results are discussed in terms of the influence of oxygen isotopic substitution on phase segregation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Growth and Investigation of Oxide Heterostructures Based on Half-Metallic Fe$\text{}_{3}$O$\text{}_{4}$
Autorzy:: Vengalis, B.
Šliužienė, K.
Lisauskas, V.
Tematy:: 75.47.Gk
75.47.Lx
07.57.Kp; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2038160.pdf Link otwiera się w nowym oknie
Opis:: We report thin films of ferromagnetic Fe$\text{}_{3}$O$\text{}_{4}$ (magnetite) grown by a reactive magnetron sputtering at T=300÷450°C on lattice-matched MgO, and bilayer structures composed of Fe$\text{}_{3}$O$\text{}_{4}$ and underlying epitaxial films of highly conductive electron-doped In$\text{}_{2}$O$\text{}_{3}$〈Sn〉, LaNiO$\text{}_{3}$, and antiferromagnetic CoO. The prepared Fe3O4/MgO films and the bilayer structures demonstrated clearly defined resistance anomaly at Verwey transition point (T$\text{}_{V}$≈100-120 K). Formation of high resistance interlayer was indicated between the adjacent conducting Fe3O4 and LaNiO3 layers. However, relatively low interface resistivity of about 0.1 Ω cm$\text{}^{2}$ (at T=300 K) was estimated for the patterned Fe3O4/In2O3〈Sn〉 bilayer structures. Vertical electrical transport measurements revealed strong nonlinearity in the I-U dependences of the Fe3O4/In2O3 〈Sn〉 interface at T
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Frequency Dependence of Electrical Response of Polycrystalline LCMO Thin Films
Autorzy:: Ašmontas, S.
Anisimovas, F.
Balevičius, S.
Cimmperman, P.
Gradauskas, J.
Lučun, A.
Stankevič, V.
Sužiedėlis, A.
Vengalis, B.
Žurauskienė, N.
Tematy:: 75.47.Gk
75.47.Lx
07.57.Kp; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2041721.pdf Link otwiera się w nowym oknie
Opis:: Influence of strong electric field in wide frequency range (from DC to 35 GHz) on electrical resistance of thin La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$ polycrystalline manganite films was investigated in the range of (78÷300) K. Different behavior of resistance change vs. temperature was observed when pulsed DC electric field and microwaves were applied to the films. When pulsed DC electric field is applied the electric-field-induced resistance change ("electroresistance") of manganite film depended nearly monotonically on temperature. However, in microwave electric fields a non-monotonic character of the electroresistance temperature dependence was observed. The dependence of the electroresistance on quality of manganite films was observed in case of microwaves. The experimental findings are explained assuming different electrical current mechanisms in case of DC and microwave fields. The applied voltage drops mainly across the grains of polycrystalline film due to a presence of displacement currents in case of microwaves, whereas in DC case the voltage drop is across the grain boundaries.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Novel Properties of Atomically Arranged Perovskites
Autorzy:: Dabrowski, B.
Kolesnik, S.
Chmaissem, O.
Suescun, L.
Mais, J.
Tematy:: 75.47.Lx
75.47.Gk
61.12.Ld; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047207.pdf Link otwiera się w nowym oknie
Opis:: Perovskites AMO$\text{}_{3-δ}$ attain unique electronic, magnetic, ferroelectric, thermoelectric, mixed-conducting, and other functional properties through selection of the A- and M-site ions, their fractions, ionic sizes and valences, spin states, and orbital orderings, as well as the oxygen content and vacancy ordering. We illustrate here our systematic exploration of the effects of composition, temperature, pressure, and oxygen content on the thermodynamic stability and magnetic properties for La$\text{}_{1-x-y}$Sr$\text{}_{x}$Ba$\text{}_{y}$MnO$\text{}_{3}$ manganites. Parameters controlling magnetic transitions are identified through examples of single-valent compounds of RMnO$\text{}_{3}$ (the Mn-O-Mn bond angles that can be equivalently described in terms of the tolerance factor) and Sr$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$ (the tolerance factor and disorder described in terms of the variance of A-site ion sizes), and the mixed-valent La$\text{}_{0.5}$Sr$\text{}_{0.5-y}$Ba$\text{}_{y}$MnO$\text{}_{3}$ (the tolerance factor, variance of sizes, and the local strains described in terms of the elongated Mn-O bonds). By using an example of kinetically stable, atomically-ordered layered-perovskites we show that improved useful properties, such as the increase in the Curie temperature T$\text{}_{C}$ and enhancement of colossal magneto-resistive effect at room temperature, can be achieved through decreases in structural distortions such as variance of sizes and local strains.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Reversible Resistive Switching in Electrically Nonhomogeneous $La_{0.67}Ca_{0.33}MnO_3$ Thin Films by Short Electrical Pulses
Autorzy:: Lučun, A.
Kiprijanovič, O.
Ašmontas, S.
Anisimovas, F.
Maneikis, A.
Sužied.lis, A.
Vengalis, B.
Tematy:: 75.47.Gk
75.47.Lx
07.57.Kp; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813407.pdf Link otwiera się w nowym oknie
Opis:: Resistance changes in thin electrically nonhomogeneous $La_{0.67}Ca_{0.33}MnO_3$ films were investigated using electrical pulses of nanosecond duration in the 80-300 K temperature range. Two types of reversible switching to higher resistive states with different starting temperature induced by series of the positive pulses were observed. Possible mechanisms of the resistance switching by short electrical pulses in the vicinity of $T_m$ and at 80-90 K are discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Laser Induced Self-Organization of Nanohills/Nanowires in $SiO_2$/Si Interface
Autorzy:: Medvid, A.
Onufrijevs, P.
Dmitruk, I.
Pundyk, I.
Tematy:: 75.47.Gk
75.47.Lx
07.57.Kp; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813410.pdf Link otwiera się w nowym oknie
Opis:: The aim of this work is to study optical properties of self-organized Si nanohills formed on the $SiO_2$/Si interface after pulsed Nd:YAG laser irradiation. Nanohills on Si surface give strong photoluminescence in the visible range of spectrum, with a long wing in red portion. This property is explained by charge carrier quantum confinement in nanohills/nanowires.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Influence of Pressure on Magnetic Properties of La$\text{}_{1-x}$ Sr$\text{}_{x}$CoO$\text{}_{3-δ}$(x=0.5, 0.67, 1)
Autorzy:: Piętosa, J.
Wiśniewski, A.
Puźniak, R.
Kolesnik, S.
Majjiga, M.
Dabrowski, B.
Tematy:: 75.30.-m
75.47.Gk
75.30.Kz; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2046737.pdf Link otwiera się w nowym oknie
Opis:: Influence of pressure on the phase transition temperature T$\text{}_{C}$ and on the spontaneous magnetisation M$\text{}_{0}$ of highly Sr substituted and oxygen nonstoichiometric La$\text{}_{1-x}$Sr$\text{}_{x}$CoO$\text{}_{3-δ}$ samples was investigated. An increase in T$\text{}_{C}$ and M$\text{}_{0}$ with pressure in investigated samples was found, indicating strengthening of ferromagnetic double exchange interactions, and the expansion of volume of ferromagnetic phase as a~result of enhancement in ferromagnetic interactions in both cluster-glass and long range ferromagnetic states. We did not observe clear correlation between changes in pressure coefficient dT$\text{}_{C}$/dP and changes in the formal oxidation state of the Co ion.
Dostawca treści:: Biblioteka Nauki

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