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Series of Al2O3(0001)/Pt/(Fe/Pt)n/Pt multilayers with variable number of bilayers n and thicknesses of individual layers were grown using molecular beam epitaxy to investigate influence of buffer layer structure, number of bilayers, and individual layer thickness on their structural and magnetic properties. Both columnar and monocrystalline 10 nm Pt (111) buffer layers were used in the experiment. Structure of Pt buffer layer determined the roughness of Fe/Pt interfaces and consequently magnetic properties of the multilayers. When multilayers were deposited on columnar Pt buffer layer, we observed increase of Fe/Pt interfaces roughness with increasing number of bilayers to values exceeding the nominal Fe/Pt bilayer thickness in the upper part of the sample volume, which resulted in the increment of coercivity in the sample with n = 15 determined from hysteresis loops measured for perpendicular orientation of magnetic field. When Fe/Pt multilayers were deposited on monocrystalline Pt buffer layer, Fe/Pt interfaces were smooth regardless the number of bilayers. All samples, despite of the quality of buffer layer, number of bilayers, and individual layer thickness revealed easy magnetisation axis oriented in the sample plane. [ABSTRACT FROM AUTHOR]

We report on preparation and electrical characterization of the epitaxial BaTiO3 (BTO), BiFeO3 (BFO) thin films and BFO/BTO bi- and multilayers, grown on (001) SrTiO3 (STO) and (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) substrates. The ferroelectric properties were characterized using the electric force microscopy method to image and switch the electric domains. This fabrication process opens the routes towards wide study of magnetoelectric effect in complex oxide heterostructures. [ABSTRACT FROM AUTHOR]

In this paper we report on the analysis of Al+-implanted ZnO/GaN bilayers in search for the damage production mechanism and possible ion mixing. 100 nm or 200 nm thick ZnO epitaxial layers were grown on GaN substrates by either sputter deposition or atomic layer deposition technique followed by adequate annealing. Ion irradiations of ZnO/GaN were carried out at room temperature using 200 keV Al+ ions with fluences of 2 x 1015 and 1016 at./cm². Unprocessed and irradiated samples were characterized by the Rutherford backscattering spectrometry in channeling geometry (RBS\c), X-ray diffraction and transmission electron microscopy. Additionally, secondary ion mass spectrometry was employed for the aforementioned samples as well as for the implanted samples subjected to further annealing. It was found that the damage distributions in ZnO/GaN differ considerably from the corresponding defect profiles in the bulk ZnO and GaN crystals, most probably due to an additional strain originating from the lattice mismatch. Amount of intermixing appears to be relatively small; apparently, efficient recombination prevents foreign atoms to relocate to large distances. [ABSTRACT FROM AUTHOR]

Ar–O–Zn plasma discharges created during DC reactive magnetron sputtering of a Zn target and RF reactive magnetron sputtering of a ceramic ZnO target were investigated and compared by means of the Langmuir probe measurements in order to determine the mechanism of growth of porous Zn films during DC-mode Zn reactive sputtering. The power supplied to the magnetrons during the sputtering was kept at 125 W and the plasma was characterised as a function of oxygen content in the sputtering gas mixture, ranging from 0 to 60% for two gas pressures related to porous Zn film deposition, namely 3 mTorr and 5 mTorr. Based on the correlation of plasma properties measurements with scanning electron microscope imaging and X-ray diffraction of the films deposited under selected conditions it was found that the growth of porous, polycrystalline Zn films was governed by high electron density in the plasma combined with a high electron temperature and an increased energy of the ions impinging on the substrate. [ABSTRACT FROM AUTHOR]

Several few µm thick (001)-oriented, metastable MnTe layers with the zinc blende structure grown onto (001)GaAs substrate by MBE during different periods for the last twenty years were investigated by the scanning electron microscopy, atomic force microscopy, X-ray diffraction, and nanoindentation methods. A partial decomposition of the oldest investigated layers was demonstrated. An important decrease of Young's modulus from about 34 GPa to about 17 GPa, resulting from a deterioration of the crystal structure of such layers, was found. [ABSTRACT FROM AUTHOR]

In-Ga-Zn-O thin films were fabricated by means of reactive RF magnetron sputtering. Mechanism of free electrons generation via oxygen vacancies formation is proposed to determine the relationship between oxygen content in the deposition atmosphere and the transport properties of IGZO thin films. The depletion-mode a-IGZO thin film transistor with field-effect mobility of 12 cm2/(V s) has been demonstrated. [ABSTRACT FROM AUTHOR]

Granular GaAs:(Mn,Ga)As films were prepared by annealing at 500°C under ambient and enhanced hydrostatic pressure (1.1 GPa), of Ga1-xMnxAs/GaAs layers (x = 0.025, 0.03, 0.04, 0.05 and 0.063) grown at 230 °C by molecular beam epitaxy method. Distinct influence of enhanced hydrostatic pressure applied during sample annealing on strain state of inclusions was found. An increase of lattice distortion and of strain of inclusions for the samples treated under hydrostatic pressure is related to different bulk moduli of GaAs and of MnAs. [ABSTRACT FROM AUTHOR]

The recent successful growth of single, bulk Pb1-xCdxTe crystals by self-selecting vapor transport method at the Institute of Physics of the Polish Academy of Sciences in Warsaw opened new opportunities to study the physical properties of this interesting material in detail. In this work we report the preliminary results of X-ray powder diffraction studies performed on a set of Pb1-xCdxTe solid solutions (where x ≤ 0.056) at high temperatures (295 K ≤ T ≤ 1100 K) and analyzed with the Rietveld refinement. Our results demonstrate the necessity of some correction of the relevant phase diagram and of the solubility limit, known from the literature. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) is a very promising material for optoelectrical devices operating at the short-wavelength end of the visible spectral range and at the near UV. The Raman scattering studies of ZnO heterolayers formed by isothermal annealing show sharp phonon lines. In addition to the A1(TO), E1(TO), E2H, and E1(LO) one-phonon lines, we observed two-phonon lines identified as: E2H - E2L, E2H + E2L , and 2LO at 332, 541, and 1160 cm-1, respectively (at room temperature). The identification of the E2H - E2L peak was confirmed by its thermal dependence. Temperature dependent measurements in the range 6-300 K show that the phonon frequencies decrease with temperature. The EH 2 peak is at energy 54.44 meV (439.1 cm-1), at 4 K and due to phonon-phonon anharmonic interaction, its energy decreases to 54.33 meV (438.2 cm-1) at room temperature. The Grüneisen parameter found for this oscillation mode was γE2H = 1.1 at about 300 K. The intensity of the E2H + E2L peak increases strongly with temperature and this dependence can be described by the Bose-Einstein statistics with activation energy of 13.8 meV (nearly equal to the energy of the E2L phonon). [ABSTRACT FROM AUTHOR]

ZnO (0001) layers on sapphire (0001) substrates were fabricated by means of high temperature high vacuum magnetron sputtering. The layers were deposited onto a thin MgO buffer and a low temperature ZnO nucleation layer, which is a technology commonly used in MBE ZnO growth. This paper reports on using this technology in the sputtering regime. [ABSTRACT FROM AUTHOR]

We report on an approach to fabricate ZnTe-based core/shell radial heterostructures containing ZnO, as well as on some of their physical properties. The molecular beam epitaxy grown ZnTe nanowires constituted the core of the investigated structures and the ZnO shells were obtained by thermal oxidation of ZnTe NWs. The influence of the parameters characterizing the oxidation process on selected properties of core/shell NWs were examined. Scanning electron microscopy revealed changes of the NWs morphology for various conditions of the oxidation process. X-ray diffraction, high resolution transmission electron microscopy, and Raman scattering measurements were applied to reveal the presence of ZnTe single crystal core and polycrystalline ZnO-shell of investigated structure. [ABSTRACT FROM AUTHOR]

GaMnSb/GaSb(100) layers with embedded MnSb inclusions have been grown at 720 K using MBE technique. This paper presents the investigation of the defect structure of Ga1-xMnxSb layers with different content of manganese (up to x = 0:07). X-ray diffraction method using conventional and synchrotron radiation was applied. Dimensions and shapes of inclusions were detected by scanning electron microscopy. Depth profiles of elements were measured using secondary ion mass spectroscopy technique. [ABSTRACT FROM AUTHOR]