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1
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Growth and Structural Characterisation of V/Fe Multilayers

100%
Marczyńska A., Skoryna J., Szymański B., Smardz L.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
552-554
EN
The (110) oriented V/Fe multilayers were prepared at room temperature using UHV magnetron sputtering. As a substrate we have used Si(100) wafers with an oxidised surface. The surface chemical composition and the cleanness of all layers was checked in situ, immediately after deposition, transferring the samples to an UHV analysis chamber equipped with X-ray photoelectron spectroscopy. The structure of the multilayers has been studied ex situ by low- and high-angle X-ray diffraction. The modulation wavelength was determined from the spacing between satellite peaks in the X-ray diffraction patterns. Results were consistent with the values obtained from total thickness divided by the number of repetitions. Growth of the Fe (V) on 1.6 nm V (Fe) underlayer was studied by succesive deposition and X-ray photoelectron spectroscopy measurements starting from 0.2 nm of Fe (V) layer, respectively. From the exponential variation of the X-ray photoelectron spectroscopy Fe 2p and V 2p integral intensities with increasing layer thickness we conclude that the Fe and V sublayers grow homogeneously in the planar mode.
2
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Oxidation Kinetics of Thin and Ultrathin Fe Films

100%
Marczyńska A., Skoryna J., Lewandowski M., Smardz L.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
549-551
EN
We have studied oxidation kinetics of Fe thin films under atmospheric conditions using the fact that metallic iron is a ferromagnet but ultrathin natural iron oxides are practically nonmagnetic at room temperature. As a consequence, oxidation is associated with a loss in ferromagnetism. Fe thin films were deposited onto 1.5 nm V thick buffer layer using UHV magnetron sputtering. As a substrate we have used Si(100) wafers with an oxidised surface. Results show that all samples with an initial Fe thickness greater than 6 nm oxidize practically instantaneously, whereby a constant amount of 2.5 nm of metal is transformed into oxides. For iron thickness lower than 6 nm the time constant for oxidation increases considerably reaching a value of 30 days for the initial Fe thickness equal to 4 nm.
3
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Strong and Weak Interlayer Exchange Coupling in V/Fe Multilayers

100%
Marczyńska A., Skoryna J., Smardz L.
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vol. 126
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issue 6
1315-1317
EN
The d_{V}-V/0.6 nm-Fe multilayers with constant thickness sublayers were prepared onto naturally oxidised Si(100) substrate using UHV (5× 10^{-10} mbar) DC/RF magnetron sputtering. Results showed that the saturation field of the V/Fe multilayers oscillate with antiferromagnetic interlayer exchange coupling peaks near the V spacer thickness of about 1.3, 1.6, 2.05 nm. Furthermore, all the samples with vanadium layer thickness near local maxima of the antiferromagnetic coupling show zero remanence. The short period of the antiferromagnetic peak oscillations is due to indirect Ruderman-Kittel-Kasuya-Yosida (RKKY)-type coupling of the Fe layers across vanadium spacer. The absence of the antiferromagnetic peaks in the very strongly coupled region (below d_{V} ≈ 1 nm) could be explained by direct ferromagnetic exchange coupling of the Fe layers due to magnetic polarization of V atoms near V-Fe interface.
4
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Hydrogen Absorption in Gd Thin Films

100%
Marczyńska A., Pacanowski S., Szymański B., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
624-627
EN
In this contribution we have studied an initial hydrogen absorption in Gd thin films using in-situ X-ray photoelectron spectroscopy (XPS) and ex-situ standard X-ray diffraction. As an initial hydrogen absorption indicator we have used broadening of the Gd-4f peak. The Gd thin films with a thickness of 200 nm were deposited at room temperature (RT) using UHV RF magnetron sputtering. As a substrate we have used naturally oxidised Si(100) wafers with 20 nm - Pd buffer layer. Furthermore, hydrogen absorption kinetics under a pressure of 100 mbar in Pd covered 200 nm Gd thin film was studied at RT using four-point resistivity measurements.
5
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XPS Valence Band Studies of LaNi_{5-x}Mₓ (M = Al, Co; x = 0, ,1) Alloy Thin Films

88%
Skoryna J., Marczyńska A., Pacanowski S., Szajek A., Smardz L.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
430-432
EN
LaNi_{5-x}Mₓ (M = Al, Co) alloy thin films were prepared onto oxidised Si(100) substrates in the temperature range of 285-700 K using UHV magnetron co-sputtering. The surface chemical composition and valence bands of all the alloy thin films were measured in situ, immediately after deposition, transferring the samples to an UHV analysis chamber equipped with X-ray photoelectron spectroscopy. Results showed that the shape of the valence bands measured for the polycrystalline samples is practically the same compared to those obtained theoretically from ab initio band structure calculations. On the other hand, the X-ray photoelectron spectroscopy valence bands of the nanocrystalline thin films (especially LaNi₄Co) are considerably broader compared to those measured for the polycrystalline samples. This is probably due to a strong deformation of the nanocrystals. Therefore, the different microstructure observed in polycrystalline and nanocrystalline alloy thin films leads to significant modifications of their electronic structure.
6
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Electronic Properties of In Situ Prepared Nanocrystalline Fe-Ni-Ti Alloy Thin Films

88%
Pacanowski S., Skoryna J., Marczyńska A., Skoryna D., Smardz L.
Acta Physica Polonica A
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2015
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vol. 127
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issue 2
436-438
EN
In this contribution we study experimentally the electronic properties of nanocrystalline Fe-Ni-Ti alloy thin films using X-ray photoelectron spectroscopy. The structure of the samples has been studied by X-ray diffraction. Their bulk chemical compositions were measured using X-ray fluorescence method. The surface chemical composition and the cleanness of all samples were checked in situ, immediately after deposition, transferring the samples to an UHV analysis chamber equipped with X-ray photoelectron spectroscopy. X-ray diffraction studies revealed the formation of nanocrystalline Fe-Ni-Ti alloy thin films at a substrate temperature of about 293 K. In situ X-ray photoelectron spectroscopy studies showed that the valence bands of nanocrystalline samples are broader compared to those measured for the polycrystalline bulk alloys. Such modifications of the valence bands of the nanocrystalline alloy thin films could influence on their hydrogenation properties.
7
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Interlayer Exchange Coupling and Proximity Effect in V-Fe Multilayers

88%
Marczyńska A., Synoradzki K., Pugaczowa-Michalska M., Toliński T., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
597-600
EN
We have studied interlayer exchange coupling (IEC) in (110) oriented V/Fe multilayers with ultrathin sublayers up to 7 monolayers (ML). Results showed that IEC energy depends on both vanadium and iron layer thicknesses. The local maxima of the antiferromagnetic coupling were found for V(7 ML)/Fe(4 ML) and V(3 ML)/Fe(3 ML) multilayers (MLs). The strongest AFM coupling energy of about 1.0 mJ/m² was measured at 5 K for the V(7 ML)/Fe(4 ML) multilayer. The position of the AFM peak for V(X ML)/Fe(3 ML) MLs near 3 ML of V spacer was also revealed by ab-initio calculations. Furthermore, theoretical calculations show an induced negative magnetic moment on V atoms near the V-Fe and Fe-V interfaces due to the proximity effect.
8
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Interlayer Exchange Coupling in Nb/Fe Multilayers

88%
Marczyńska A., Pugaczowa-Michalska M., Szymański B., Majchrzycki Ł., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
605-608
EN
The (110) oriented Nb-Fe multilayers (MLs) with constant Fe and variable Nb sublayer thicknesses were prepared at room temperature using UHV magnetron sputtering. The artificial periodicity was revealed by intense satellite peaks in the low- and high-angle X-ray diffraction patterns. Magnetic hysteresis loop measurements at 5 K revealed antiferromagnetic (AF) exchange coupling of the Fe sublayers for Nb spacer thickness of about 3 monolayers. The corresponding AF coupling energy is equal to about -1.36 mJ/m². The Nb spacer thickness corresponding to the position of the AF peak is in good agreement with ab-initio calculations within localized spin density approximations of exchange-correlation potential.
9
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Modification of Exchange Coupling in Fe/Nb/Fe/Pd Layered Structures using Hydrogen

76%
Wachowiak M., Marczyńska A., Dawczak-Dębicki H., Pugaczowa-Michalska M., Pacanowski S., Majchrzycki Ł., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
609-612
EN
Fe/Nb/Fe trilayers were prepared at room temperature using UHV magnetron sputtering. The interlayer exchange coupling energy was determined from a shift of the minor hysteresis loop from the origin. Results showed clear antiferromagnetic (AF) coupling maxima near ım6 and 9 monolayers of Nb spacer. Calculations of the interlayer exchange coupling energy were carried out using ab-initio method with localized spin density approximations of exchange-correlation potential. The experimental results were in good agreement with ab-initio calculations. Furthermore, the position of the AF peaks and coupling energy values could be modified using hydrogen.
10
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Magnetisation and Hydrogenation of Mg/Ni Multilayers

76%
Pacanowski S., Marczyńska A., Dawczak-Dębicki H., Jabłoński B., Szymański B., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
617-619
EN
In this contribution we have studied magnetisation of Mg/Ni multilayers (MLs) to characterise the alloing effect near interfaces. The layered structure was characterised by standard X-ray diffraction. The MLs were deposited by UHV magnetron sputtering onto naturally oxidised Si(100) substrates. Results showed, that due to Mg-Ni alloy formation near interfaces the magnetizations of the MLs were strongly reduced. Effective "dead" Ni layer thickness was estimated as 1.2 nm at room temperature (RT). Furthermore, hydrogen absorption kinetics at a pressure of about 1000 mbar was studied at RT in Pd covered Mg/Ni MLs using four-point resistivity measurements. Results showed that the fastest initial rise in resistance in the first 9 s was observed for d_{Ni}=3.5 nm.
11
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Influence of Valence Band Modifications on Hydrogen Absorption in Zr-Pd Alloy Thin Films

76%
Jabłoński B., Pacanowski S., Werwiński M., Marczyńska A., Dawczak-Dębicki H., Szajek A., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
620-623
EN
We study the valence band modifications of in-situ prepared nano- and polycrystalline Pd-Zr alloy thin films using X-ray photoelectron spectroscopy. Results were compared with valence bands calculated by ab initio methods. Furthermore, hydrogen absorption and desorption kinetics under pressure of about 570 mbar were studied in Pd covered nanocrystalline ZrPd₂ alloy thin film. Results showed that modifications of the valence band of the nanocrystalline alloy thin film could significantly influence on hydrogen absorption and desorption process.
12
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XPS and UPS Valence Band Studies of Nanocrystalline Ni-Ti Alloy Thin Films

64%
Pacanowski S., Skoryna J., Szajek A., Marczyńska A., Dawczak-Dębicki H., Werwiński M., Majchrzycki Ł., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
613-616
EN
In this contribution we study valence bands of in-situ prepared nanocrystalline NiTi and Ni₃Ti alloy thin films using X-ray and ultraviolet photoelectron spectroscopy. Additionally, theoretical valence band of NiTi alloy was calculated by ab-initio methods. The structure and morphology of the samples were studied by X-ray diffraction and atomic force microscopy, respectively. Furthermore, hydrogen absorption and desorption kinetics at a pressure of about 1000 mbar were studied in Pd covered nanocrystalline NiTi alloy thin film using four-point resistivity measurements. Results showed that modifications of the valence bands of the Ni-Ti thin films due nanocrystalline structure can influence on the room temperature hydrogen absorption and desorption kinetics.
13
Content available remote

Exchange Coupling Effects in Naturally Oxidised Ultrathin Iron Film

64%
Dawczak-Dębicki H., Marczyńska A., Rogowska A., Wachowiak M., Nowicki M., Pacanowski S., Jabłoński B., Czajka R., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
601-604
EN
Oxidation process of Fe films under atmospheric conditions is depth limited such that an oxide covering layer with a well-defined thickness is formed by which the underlying metal is prevented from further oxidation. Iron thin film with an initial thickness d_{i}=4 nm was deposited onto 1.6 nm - V(110) buffer layer using UHV magnetron sputtering. The planar growth of Fe oxides was revealed by atomic force microscopy. X-ray photoelectron spectroscopy studies performed after 250 days of oxidation revealed formation of a hematite (α-Fe₂O₃) ultrathin film on the metallic rest of iron. Furthermore, low temperature magnetic measurements of the oxidised Fe ultrathin film revealed an exchange anisotropy which is imposed to the metallic rest. As a result, we have observed at low temperatures a shift and broadening of the hysteresis loops due to the exchange interaction at the metal-oxide interface.
14
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Preparation and Characterisation of Fe/Ce Multilayer

64%
Dawczak-Dębicki H., Marczyńska A., Pacanowski S., Szymański B., Majchrzycki Ł., Kowalski W., Grembowski W., Bilski T., Smardz L.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
628-631
EN
Ce/Fe multilayer (ML) with constant Fe (2 nm) and Ce (4.5 nm) sublayer thicknesses was prepared onto naturally oxidised Si(100) substrate using magnetron sputtering. Chemical purity of the sublayers was revealed in-situ by X-ray photoelectron spectroscopy (XPS) measurements. The structure of the sample was studied by standard low- and high-angle X-ray diffraction (XRD). Surface morphology of the ML was examined by atomic force microscopy. Magnetic properties of the sample was studied in the temperature range between 5 and 350 K using a vibrating sample magnetometer in a magnetic field up to 9 T. The hysteresis loops were measured in field perpendicular and parallel to the substrate. Furthermore, hydrogen absorption at a pressure of about 1000 mbar was studied at room temperature (RT) in Pd covered ML using four-point resistivity measurements. The solid state amorphisation reaction have been confirmed by XRD and magnetic measurements of the Ce/Fe ML. The absence of satellite peaks in the low - angle XRD pattern revealed no artificial layered structure. The above results show that interdiffusion of cerium and iron atoms is extremely fast at RT.
15
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Natural Oxidation of thin Fe Films on V Buffer Layer

52%
Dawczak-Dębicki H., Marczyńska A., Rogowska A., Wachowiak M., Nowicki M., Pacanowski S., Jabłoński B., Kowalski W., Grembowski J., Czajka R., Smardz L.
Acta Physica Polonica A
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2017
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vol. 132
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issue 4
1272-1276
EN
We have studied oxidation kinetics of Fe thin film under atmospheric conditions using the fact that metallic iron is a ferromagnet but ultrathin natural iron oxides are approximately nonmagnetic at room temperature. As a consequence, oxidation is associated with a loss in total Fe magnetic moment. Results show that the sample with an initial Fe thickness equal to 10 nm oxidize relatively fast (time constant τ=0.05 day), whereby a constant amount of 2.5 nm of metal is transformed into oxides. For lower iron initial thickness (d_{i}=4 nm) the time constant for oxidation significantly increases reaching a value of 2 days. Furthermore, X-ray photoelectron spectroscopy studies performed after 144 days of oxidation revealed formation of hematite (α-Fe₂O₃) thin film on the metallic rest of iron.
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