Wyniki wyszukiwania - Biblioteka Nauki

1

STM Observations of Ferromagnetic Clusters

100%

Wawro A. , Kasuya A.

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nr 2

443-448

EN

Co, Fe and Ni clusters of nanometer size, deposited on silicon and graphite (highly oriented pyrolytic graphite), were observed by a scanning tunneling microscope. Deposition as well as the scanning tunneling microscope measurements were carried out in an ultrahigh vacuum system at room temperature. Detailed analysis of Co cluster height was done with the scanning tunneling microscope equipped with a ferromagnetic tip in the magnetic field up to 70 Oe. It is found that bigger clusters (few nanometers in height) exhibit a dependence of their apparent height on applied magnetic field. We propose that such behaviour originates from the ferromagnetic ordering of cluster and associate this effect to spin polarized tunneling.

2

STM/STS Studies of Self-Organized Growth of Iron Silicide Nanocrystals on Vicinal Si(111) Surface

80%

Wawro A. , Suto S. , Czajka R. , Kasuya A.

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nr 3-4

303-319

EN

The evolution of iron silicide structure grown by solid state epitaxy on Si(111) vicinal surface was investigated by scanning tunnelling microscopy. The reactions, which occur on the surface, are compared for two various Fe coverages: 0.33 and 2 monolayers. The annealing at 250˚C does not enable substantial recovery of the surface ordering, deteriorated by Fe deposition at room temperature. The onset of 2×2 surface reconstruction is observed upon annealing at 400˚C. A three-dimensional growth tendency of iron silicide crystallites on a bare Si(111) 7×7 surface was found at 700˚C. In the case of 2 monolayer coverage crystallites nucleate along the edges of substrate terraces forming a regular array of nanometer size dots. Basing on atomically resolved spectroscopic effects and statistical considerations, structure of iron silicide nanocrystallites as well as Schottky-like character of the barrier at the interface between metallic crystallite and semiconducting substrate is deduced.

3

Stm Observed Surface Structures and Magnetic Properties of MBE-Grown Metallic Thin Films

71%

Kalinowski R. , Baczewski L. , Wawro A. , Meyer C. , Raułuszkiewicz J.

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nr 2

409-413

EN

Rare-earth epitaxial thin films of Tb and Gd of the thicknesses between 2 nm and 16 nm were deposited by means of molecular beam epitaxy method. The roughness of the rare-earth films measured by scanning tunneling microscopy was found to be in the range of 1-4.5 nm. The influence of the roughness on the dipolar anisotropy and magnetocrystalline surface anisotropy was estimated. The magnetic measurements have shown that the Gd layers deposited on the Y buffer layers had an easy plane anisotropy. However, for 2 nm thick Gd layer deposited on W buffer layer the perpendicular anisotropy was observed. According to the roughness analysis the possible sources of the perpendicular anisotropy in this sample is mainly the magnetoelastic anisotropy, but the presence of the magnetocrystalline surface anisotropy also cannot be neglected.

4

STM/AFM Observations of Co/Cu Magnetic Multilayers

61%

Aleszkiewicz M. , Kalinowski R. , Czajka R. , Polewska W. , Wawro A. , Baczewski L. T. , Raułuszkiewicz J.

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nr 2

311-314

EN

UHV deposited magnetic Co/Cu multilayers were investigated by means of scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Surface of the sample i.e. upper covering layer in "plane" configuration and individual sublayers in "cross-section" configuration were investigated. A possibility of structure characterization of metallic multilayers by STM and AFM in the cross-section configuration is demonstrated.

5

Structure and Magnetism of MBE-Grown Co/Cu Multilayers

61%

Baczewski L. T. , Wawro A. , Domagała J. , Pełka J. , Szewczyk A. , Nabiałek A.

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nr 2

315-319

EN

Structural and magnetic properties of Co/Cu multilayers deposited in the ultra-high vacuum molecular beam epitaxy system on glass substrates with different modulations periods were investigated. A structural characterization was performed by means of RHEED and Auger spectroscopy (in situ), small angle X-ray reflectivity and scanning tunneling microscopy. The samples obtained have a textured, polycrystalline layered structure for deposition at room temperature. Magnetization and in-plane magnetoresistance measurements were performed as a function of Cu and Co layer thicknesses. An influence of different buffers and of interface quality on magnetic properties was investigated.

6

Chemical Reactions and Electronic Functions of Carbon Cluster Arrays Studied by Scanning Tunneling Spectroscopy and High-resolution Electron Energy Loss Spectroscopy

51%

Kasuya A. , Hu C. , Suto S. , Tohji K. , Takahashi H. , Czajka R. , Wawro A. , Nishina Y.

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nr 2

317-322

EN

Novel nanometer scale structures have been produced by thermal heating or laser irradiation on the surface of single- and multi-layers of C_{60} and C_{84} on Si. These structures were examined by combined measurements of scanning tunneling spectroscopy and high resolution electron energy loss spectroscopy. The results show specific chemical reactions of substrate with carbon clusters having single- and double-bonded network. Covalent bonds are formed in some of these chemical reactions.

7

THz Time Domain Spectroscopy of Thin Gold Layers on GaAs

51%

Szczytko J. , Adomavicius R. , Papis E. , Barańska A. , Wawro A. , Krotkus A. , Piętka B. , Łusakowski J.

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nr 6

1118-1120

EN

Thin layers of Au with the thickness of several nanometers were prepared on a semi-insulating GaAs substrate. The layers' thickness was determined by ellipsometry. THz time-domain spectroscopy was applied to determine a complex index of refraction of thin Au layers. The obtained results allow for a more precise modeling of the performance of semiconductor devices at THz frequencies.