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1

Ferromagnetic Resonance Studies of La_{0.67}Ca_{0.33}MnO_3 Film under Stress

100%

Kundys B., Dyakonov V., Baran M., Gierłowski P., Szymczak R.

Acta Physica Polonica A

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2004

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vol. 105

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issue 1-2

133-139

EN

Ferromagnetic resonance spectra of the La_{0.67}Ca_{0.33}MnO_3 ferromagnetic film deposited onto the x-cut LiNbO_3 substrate were investigated in a wide temperature range. The strain was mechanically introduced into the film using a special holder configuration. This leads to a shift of resonance field with respect to that of the as-grown sample. Analysis of the magnetic resonance shift, induced by a mechanical stress, allowed us to determine the magnetostriction constant λ_{100}. The magnetostriction determined in this way versus saturation magnetization could be well described by the Callen and Callen theory suggesting the domination of the single ion crystal field interaction in the sample being in the ferromagnetic state.

2

La_{0.7}Sr_{0.3}MnO_3 Thin-Film Grain-Boundary Junctions on a Bi-Crystal Substrate

86%

Gierłowski P., Szewczyk A., Abal'oshev A., Vlakhov E., Donchev T., Blagoev B.

Acta Physica Polonica A

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2004

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vol. 106

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issue 5

715-719

EN

Transport properties of 10μm to 30μm wide grain-boundary junctions ion-etched in thin colossal magnetoresistance La_{0. 7}Sr_{0.3}MnO_3 films deposited on a SrTiO_3 bi-crystal were investigated. We have measured the current-voltage characteristics in the temperature range from 4.2 K to 300 K without applied magnetic field, as well as the magnetoresistance at magnetic fields up to±10 kOe directed parallel to the film surface, both perpendicular and parallel to the direction of current flow through the junctions. The investigated junctions have nonlinear current-voltage characteristics in this temperature range and consist of several magnetic domains. The maximum magnetoresistance (R(H)-R _{max})/R_{max}, measured at 1 kOe was -17.6% at 4.1 K.

3

Study of Si-Implanted and Thermally Annealed Layers of Silicon by Using X-ray Grazing Incidence Methods

86%

Klinger D., Lefeld-Sosnowska M., Pełka J., Paszkowicz W., Gierłowski P., Pankowski P.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

795-801

EN

This paper reports on the study of structural modifications induced by the implantation process and by the subsequent thermal annealing in near-surface layers of Si single crystals implanted with Si^{2+} ions of energy 140 keV and doses from 1×10^{15} to 1× 10^{16} ions/cm^2. The grazing incidence X-ray diffraction and X-ray reflectivity measurements were applied to determine the thickness and structural composition of the damaged layers. The fitted electron density profiles indicated an existence of an interfacial layer with density higher than the density of Si matrix or near-surface oxide layer. Formation of polycrystalline phases of silicon and silicon oxides is discussed in dependence on the conditions of annealing treatment and implantation dose.

4

X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

86%

Pełka J., Paszkowicz W., Gierłowski P., Lewandowski S., Zieliński M., Barbanera S., Knapp M.

Acta Physica Polonica A

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2002

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vol. 101

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issue 5

787-794

EN

Grazing-incidence X-ray diffraction supplemented with atomic force microscopy and secondary ion mass spectroscopy were applied to the characterization of films deposited by laser ablation on cold substrates from YBaCuO targets and subsequently irradiated with additional laser pulses of lower energy density. Evolution of X-ray diffraction pattern was observed as a function of irradiation dose. For the as-deposited films the pattern was typical of the amorphized solids. For the films irradiated with doses higher than the threshold, the pattern was enriched with the diffraction peaks, whose general features, like peak positions, widths and relative intensities were almost independent of the dose. The size of the crystallites was deduced from the peak widths to be not smaller than 12-16 nm. Comparison of the pattern with patterns of known phases indicates that, apart of the amorphous component, a structure with an admixture of some new metastable or high temperature phase(s) is formed during the process of pulsed laser annealing. The atomic force microscopy observations revealed that the surface roughness shows a pronounced minimum at low irradiation doses. The secondary ion mass spectroscopy investigation confirms that the strongest chemical changes (increase in concentration of yttrium and copper) due to irradiation with higher doses are observed in the near-surface film material.

5

Atomic Order and the Interaction of Electronic and Magnetic Subsystems in Epitaxial LaSr(Ca)MnO Films

73%

Okunev V., Samoilenko Z., D'yachenko T., Abal'oshev A., Baran M., Gierłowski P., Lewandowski S., Szewczyk A., Szymczak R.

Acta Physica Polonica A

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2004

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vol. 105

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issue 1-2

121-126

EN

We have investigated the structure, and electric, optical, and magnetic properties of LaSr(Ca)MnO films containing atomic clusters of various types coherently built into the basic crystallographic matrix. Below the transition to the metallic state, the electrical conductivity of the films is determined by tunneling of charge carriers between metallic clusters. We have found that for each sample there exists a threshold value of magnetic ordering, above which the magnetic subsystem starts to affect actively the film conductivity. The observed increase of conductivity with decreasing temperature is caused by the fact that in the process of magnetic ordering of the samples the cluster size and concentration of metallic phase increase. Experimental results are in agreement with theoretical calculations.

6

Mesoscopic Ordering Effects in Single-Crystalline Thin Films of Lanthanum Manganites

73%

Samoilenko Z., Okunev V., Pushenko E., Abal'oshev A., Baran M., Gierłowski P., Lewandowski S., Szymczak R.

Acta Physica Polonica A

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2004

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vol. 105

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issue 1-2

93-98

EN

We have investigated thin films of lanthanum manganites epitaxially grown by pulsed laser deposition on single-crystalline substrates. X-ray diffraction studies show that the characteristic feature of the investigated films is a superposition of fractions with long range atomic order in the basic single-crystalline matrix, and mesoscopic order in the clusterized structure encompassing the Mn-O layers. A detailed analysis of diffusive scattering shows that the size of metallic clusters and their volume concentration in the dielectric matrix varies. In the case of a small size and concentration, the metallic clusters in low temperature behave as quantum dots and their presence leads to a tunneling mechanism of conductivity with characteristic R(T)= const. In the case of large cluster size, the discrete energy levels become smeared. It appears also that the optical, transport, and magnetic properties of the investigated films depend critically on the distribution of Mn^{2+}, Mn^{3+}, and Mn^{4+} ions in the clusters.

7

Growth and Characterization of YBa_2Cu_3O_{7-δ} Films Deposited by Laser Ablation on CeO_2-Buffered Sapphire

73%

Abal'osheva I., Zaytseva I., Aleszkiewicz M., Malinowski A., Bezusyy V., Syryanyy Y., Gierłowski P., Abal'oshev O., Kończykowski M., Cieplak M.

Acta Physica Polonica A

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2014

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vol. 126

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issue 4a

A-69-A-73

EN

In this work we study the growth, by pulsed laser deposition, of YBa_2Cu_3O_{7-δ} (YBCO) films on the CeO_2-buffered R-cut sapphire substrates, with the buffer layer recrystallized prior to the deposition of superconductor. We find that the superconducting critical temperature and the critical current density of the films are very close to similar parameters for the YBCO films grown on lattice-matched single crystalline substrates. It appears that the structural defects in the buffer layer affect the microstructure of YBCO films, resulting in high values of the critical current density, suitable for applications.

8

Optimization of the Superconducting Properties of Laser Ablated YBa_2Cu_3O_{7-δ} Films on CeO_2-Buffered Sapphire

73%

Abal'osheva I., Zaytseva I., Aleszkiewicz M., Syryanyy Y., Gierłowski P., Abal'oshev O., Bezusyy V., Cieplak M.

Acta Physica Polonica A

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2012

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vol. 121

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issue 4

805-807

EN

We use pulsed laser deposition to grow YBa_2Cu_3O_{7-δ} (YBCO) superconducting films for microwave applications. The films are grown on R-cut sapphire substrates, with CeO_2 buffer layers, which are re-crystallized at high temperature prior to YBCO growth. Using the atomic force microscopy (AFM) and X-ray diffractometry we determine the optimal temperature for recrystallization (1000°C) and the optimal buffer layer thickness (30 nm). The properties of YBCO films of various thickness, grown on the optimized CeO_2 buffer layers, are studied using several methods, including AFM, magnetooptical imaging, and transport experiments. The YBCO film roughness is found to increase with the increasing film thickness, but the magnetic flux penetration in the superconducting state remains homogeneous. The superconducting parameters (the critical temperature and the critical current density) are somewhat lower than the similar parameters for YBCO films deposited on mono-crystalline substrates.

Refine search results

Ferromagnetic Resonance Studies of La_{0.67}Ca_{0.33}MnO_3 Film under Stress

La_{0.7}Sr_{0.3}MnO_3 Thin-Film Grain-Boundary Junctions on a Bi-Crystal Substrate

Study of Si-Implanted and Thermally Annealed Layers of Silicon by Using X-ray Grazing Incidence Methods

X-ray Characterization of Films Formed by Pulsed Laser Deposition on Cold Substrates from YBaCuO Targets

Atomic Order and the Interaction of Electronic and Magnetic Subsystems in Epitaxial LaSr(Ca)MnO Films

Mesoscopic Ordering Effects in Single-Crystalline Thin Films of Lanthanum Manganites

Growth and Characterization of YBa_2Cu_3O_{7-δ} Films Deposited by Laser Ablation on CeO_2-Buffered Sapphire

Optimization of the Superconducting Properties of Laser Ablated YBa_2Cu_3O_{7-δ} Films on CeO_2-Buffered Sapphire