Wyniki wyszukiwania - BazTech

1

Au/Fe3O4 and Au/Fe2O3 Catalysts: Physicochemical Properties and Oxidation of CO and Propane

Grzybowska B., Ruszel M., Samson K., Grabowski R., Spiridis N., Freindl K., Korecki J.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 12

2129-2136

EN

Catalysts containing Au deposited on Fe3O4 (commercial Cerac) and on Fe2O3 were synthesized, characterized by XPS, XRD, Mössbauer spectroscopy, H2TPR, isopropanol decomposition – a probe reaction of acid-base properties, and tested in oxidation of CO and C3H8. Au//Fe3O4 cat a lyst, containing a mixture of magnetite and maghemite (gamma-Fe2O3) phases, was found to be more acidic containing more surface OH groups and less reducible than Au/alfa-Fe2O3 (hematite). The activity in oxidation of CO and propane was higher for Au/alfa-Fe2O3 catalyst as compared with Au/Fe3O4.

2

Magnetism of ultra-thin iron films seen by the nuclear resonant scattering of synchrotron radiation

Slęzak T, Stankov S, Zajšc M, Slęzak M, Matlak K, Spiridis N, Laenens B, Planckaert N, Rennhofer M, Freindl K, Wilgocka-Slęzak D, Rüffer R, Korecki J

Materials Science Poland

|

2008

|

Vol. 26, No. 4

885--896

EN

Conversion electron Mössbauer spectroscopy proved in the past to be very useful in studying surface and ultrathin film magnetism with monolayer resolution. Twenty years later, its time-domain analogue, the nuclear resonant scattering (NRS) of synchrotron radiation, showed up to be by orders of magnitude faster and more efficient. The most important features of NRS based on simulations and experimental data have been discussed. It has been shown how the isotopic sensitivity of NRS, combined with the 57Fe probe layer concept, was explored to study influence of the interlayer exchange coupling to FeAu monoatomic superlattices on the magnetic properties of the iron monolayer on Au(001). In the second example, combination of UHV conditions and the high brilliance of the third generation synchrotron source is used to probe the evolution of spin structure in epitaxial Fe films on W(110) via the accumulation of high quality time spectra directly during the 57Fe film growth.

3

Korelacja własności magnetycznych i struktury Fe-Cr

Kąc M., Karaś W., Ślęzak T., Korecki J.

Prace Naukowe Politechniki Warszawskiej. Elektronika

|

2002

|

z. 143

171-174

EN

Conversion electron Mossbauer spectroscopy (CEMS) was applied to study Fe ultrathin films and Fe/Cr, Cr/Fe interfaces. Based on alloy model in which the Cr atom in the first and second Fe coordination shell decreases the Fe hyperfine field, we are able to show that the Cr/Fe ("lower") interface is smoother than the Fe/Cr ("upper") one. The Fe atoms are distributed over 1 and 2 atomic layers in the lower and upper interfaces, respectively. The CEMS studies were correlated with the magneto-optic Kerr effect measurements of an indirect exchange coupling in Fe/Cr multilayers. In the Fe/Cr/Fe trilayers the antiferromagnetic and non-collinear coupling was observed for the 8 ML and 20 ML Cr spacer thickness, respectively.

4

Holografia gamma - trójwymiarowe obrazowanie lokalnej struktury z rozdzielczością atomową

Korecki P., Korecki J.

Postępy Fizyki

|

2001

|

T. 52, z. 5

225-237

EN

Principles of gamma-ray holography using an internal sources/detectors scheme of holography and allowing for three-dimensional model free imaging of local atomic structure with nuclear resonant scattering of gamma-radiation (Moessbauer effect), are presented. First experimental results for a test system: 57Fe/Mg0(001) epitaxial film are discussed. The idea of complex holography, solving the twin-image problem, is presented and the possibility of studying local magnetic structure on atomic level is elucidated.