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«ANNUAL REPORT Riga 2012 Annual Report 2011, Institute of Solid State Physics, University of Latvia. Editor: A.Krumins. Composed matter: A.Muratova. ...»

-- [ Page 21 ] --

6. L.Trinkler, B.Berzina. „Photo and thermoluminescence in AlN ceramics at low temperature”, Abstract book, p. 67, Glasgow, UK, 2011.

7. B.Berzina, V.Korsaks and L.Trinkler. „Native defect luminescence of III group element nitrides - AlN and hBN bulk and nanosize”, Abstract book, p. 93, Glasgow, UK, 2011.

16th Conference on Nordic Society for Radiation protection, 22 – 25 August 2011, Reykjavik, Iceland

8. L.Trinkler and B.Berzina. „UV radiation induced processes in AlN and its potential application for solid statne dosimetry”, Abstact book, p.76, Reykjavik, Iceland, 2011.

17th Internationas Symposium on Boron, Borides and Related Materials, 11 – 17 September 2011, Istanbul, Turkey

9. V.Korsaks, B.Berzina, L.Trinkler, R.Williams and B.Ucer. „Spectral characterization of hBN powder and nanowall nanotubes”, Abstract book, p.134, Istanbul, Turkey, 2011.

–  –  –

The research interests are focused on problems related to structure and micromechanical and optical properties of surfaces, interfaces and thin films of advanced tribological and optical materials, and materials for micro/nanotechnologies (e.g. metals and alloys, oxides, halides, fullerenes and composite systems). Research area includes development of the methods of surface modification and studies of surface and interface effects in indentation hardness, plasticity and adhesion. The research is based on methods of micro- and nanoindentation, AFM, SEM, XRD and optical microscopy.

Main research topics in 2011

• Obtaining of nanostructured functional coatings by mechanoactivated oxidation and investigating their mechanical and optical properties;

• Studies of the structure and micromechanical properties of thin film systems, grain boundaries and interfaces in heterogeneous structures;

• Surface modification by irradiation with swift heavy ions.

Scientific Staff

1. Dr.phys. F.Muktepavela

2. Dr.phys. I.Manika

3. Dr.habil.phys.,emeritus J.Maniks PhD Students M.phys.G.Bakradze M.phys. R.Zabels Technical Staff A.Petersons Students

1. B.sc.R.Grants

–  –  –

1. R.Zabels, Nice, France (7 days).

2. Dr.J.Maniks, Nice, France (7 days)

3. Dr.I.Manika, St.Petersburg, Russia (7 days)

4. Dr.J.Maniks, Astana, Kazakhstan (14 days)

–  –  –

Latvia Daugavpils University, Innovative Microscopy Centre (Dr. E.Tamanis).

Institute of Physics, University of Latvia (Dr.A.Shisko).

Germany GSI, Darmstadt (Prof. K.Schwartz, Dr.M.Tomut).

Israel Technion, Haifa (Dr.S.Stolyarova).

Russia Institute of Solid State Physics RAN, Chernogolovka (Prof.B.Straumal, Dr.V.Sursajeva) Kazakhstan L. Gumilyov Eurasian National University (Dr.A.Dauletbekova)

–  –  –

SWIFT-ION-INDUCED NANOSTRUCTURING OF LiF CRYSTALS: COMPARISON

BETWEEN HEAVY AND LIGHT PROJECTILES

J.Maniks1, I.Manika1, R.Zabels1, R.Grants1,E.Tamanis2, K.Schwartz3 ISSP, University of Latvia, 8 Kengaraga Str., LV 1063 Riga, Latvia University of Daugavpils, 1 Parades Str. LV5400 Daugavpils, Latvia GSI, Darmstadt, 1 Planckstrasse, D-64219 Darmstadt, Germany Modifications of the structure of LiF crystals irradiated with swift heavy (238U, 208Au) and lighter (50Ti, 12C) ions of the specific energy of 11.1 MeV/u at fluences in the range of 1011 to 1013 cm-2 have been studied using the AFM, SEM, High-resolution XRD and nanoindentation methods. The structure was revealed by a chemical etching. The AFM and SEM studies on samples irradiated with heavy ions (238U, 197Au) showed a nanostructuring of the irradiated layer. The nanostructure consists of columnar grains with a width of about 50nm. In the case of the lightest ions (12C), the irradiation resulted in the formation of dislocation-reach structure. No bulk nanostructures were observed even at the highest fluence of 5× 1012 cm-2. For ions with an intermediate atomic mass (50Ti), either a dislocation-reach structure or a nanostructure was formed in relation to the fluence and the energy loss.

In the nanostructured layer, the rocking curves obtained by a high-resolution X-ray diffraction expose the formation of a mosaic-type structure with low-angle boundaries between blocks.

Nanoindentation tests show a strong ion-induced increase of hardness (up to 150in the nanostructured zone confirming the high volume concentration of strong obstacles for dislocations, such as grain boundaries and defect aggregates. A marked hardening demonstrates also the dislocation-rich zone. The results show that swift-ioninduced structural fragmentation and nanostructuring in LiF can be reached at definite conditions of fluency and energy loss.

–  –  –

In this work a simple method of Zn vapor condensation and oxidation in a tube furnace was utilized to obtain ZnO powders with grained (d=100-300 nm) and multipod-like (whiskers) (d=50-100 nm, l=3-10 µm) morphology. Powders were compacted at identical conditions and a following sintering performed at temperature of 1200 oC. Research included structural investigations using optical, AFM and SEM microscopies, a photoluminescence investigation for an evaluation of present defects and a nanoindentation to characterize a mechanical behavior and stability of obtained ceramics.





Ceramics sintered from the grained powder have large grains – in diameter ranging from 3 to 20 µm with an average size of about 10 µm. The surface of the ceramic is covered with large ZnO spheres which are a product of a rapid oxidation of an escaped excess Zn vapor. The porosity is high – polishing revealed that large voids with a size 10-80 µm are present throughout the volume of ceramics. Micropores are located not only at grain boundaries but inside grains as well. At 12 K besides an excitonic peak this ceramic exhibited a broad green luminescence band attributed to defect states (particularly oxygen vacancies or interstitial Zn) which is in an agreement with the SEM micrographs.

For the ceramic from the multipod-like powder grain sizes range from 1 to 10 µm with an average grain size of 4 µm. In this case micropores are present only in triple junctions of grain boundaries. No pores were detected inside the volume of grains. Luminescence at 12 K revealed a narrow excitonic band with a probable satellite peak and an almost non-existent green luminescent band which is an evidence of a high quality of ceramic sintered from whiskers powders. Mechanical properties (hardness is 3 GPa and Young’s modulus 120 GPa.) of these ceramics are high and comparable to high pressure ceramics and a single crystal ZnO.

Indentation tests have shown the specific role of the grain boundaries in the deformation behavior of ceramics. The effect of the powder morphology on the properties of sintered ceramics may be explained from the standpoint of contacts phenomena during the sintering.

Scientific publications

SCI publications

1. J. Maniks, I.Manika, R. Grants, R. Zabels, K.Schwartz, M.Sorokin, R.M.Papaleo, Nanostructuring and hardening of LiF crystals irradiated with 3-15 MeV Au ions. Applied Physics A: Materials Science and Processing 2011, vol.104, No.4, pp.1121-1128.

2. J.Maniks, I.Manika, R.Zabels, R.Grants, K.Schwartz, M.Sorokin, Modification of the structure and nano-mechanical properties of LiF crystals under irradiation with swift heavy ions. Materials Science (MEDŽIAGOTYRA) 2011,vol. 17, No. 3, pp.223-228.

3. K. Kolev, T.Petkova, C.Popov, P.Petkov, F.Muktepavela, Surface development of (As2S3)1-x(AgI) x thin films for gas sensor applications. NATO Science for Peace and Security, Series B: Physics and Biophysics, 2011, pp.203-209.

Other publications

4. V.Sursajeva, F.Muktepavela. Effect of the first order different edges on the motion of grain boundaries in Zn. Proc.9th Intern.Sci.and Tech. Conf. Advanced metal materials and technologies (AMMT’2011), June 22–24, 2011, St.Petersbugr, Russia. 400-401p.

5. E. Platacis. A Ziks, A Poznjak, F. Muktepavela, A. Shisko, S. Sarada. Corosion phenomena of FMS (P91) steel in Pb-Li flow in magnetic field. Proc. 8th PAMIR Int.

Conf. Fundamental and Applied MHD. - September 5-9, Borgo, Corsica, France, 2011, p.587-592.

6. G.Bakradze. Initial oxidation of zirconium: oxide-film growth kinetics and mechanisms PhD thesis, Max-Planck Institute, Stuttgart University, Stuttgart 2011, p.111.

7.

Lectures on Conferences International Conference on Functional materials and Nanotechnologies FM&NT 2011, April 5 –8, 2011, Riga, Latvia

1. R. Zabels, F. Muktepāvela, L. Grigorjeva, K. Kundziņš, Effect of nano-powder morphology on the properties of ZnO sintered ceramics. Book of Abstracts, PO-106, p.196..

2. J.Maniks, I.Manika, R.Zabels,R.Grants,E.Tamanis,K.Schwartz. Swift-ion-induced nanostructuring of LiF crystals: comparison between heavy and light projectiles.. Book of Abstracts, PO-107, p.197.

3. A.Dauletbekova, I. Manika, R. Zabels, R.Grants,. A.Akilbekov, M. Zdorovets.

Aggregation processes and nanostructuring in LiF crystals irradiated with 150 MeV 84Kr ions. Book of Abstracts, PO-108, p.198.

E-MRS 2011 Spring Meeting, May 9-13, 2011, Nice, France

4. J.Maniks, I.Manika, R.Zabels, R.Grants, E.Tamanis, K.Schwartz. Nanostructuring and strengthening of LiF crystals by swift heavy ions: AFM, XRD and nanoindentation study.

Symposium B, Ion Beam Synthesis and Modification of Nanostructured Materials, Programm and Abstacts, PB1-12

5. A.Dauletbekova, J. Maniks, I. Manika, M. Zdorovets, A.Akilbekov, R.Zabels, R.Grants, Y. Bikhert, D.Akilbekova.. Ion-induced modification of LiF crystal properties: fluence and flux effects. Symposium B: Ion Beam Synthesis and Modification of Nanostructured Materials, Programm and Abstacts,PB2-31.

6. R. Zabels, F. Muktepavela, L. Grigorjeva, E. Tamanis, Deformation behavior and optical properties of nanostructured ZnO films on glass, Symposium D: Synthesis, Processing and Characterization of Nanoscale Multi Functional Oxide Films, Programm and Abstacts, P1-56.

3rd International Conference “Radiation Interaction with Materials and Its Use in Technologies, 20-23 September, 2011, Kaunas, Lithuania

7. J.Maniks, I.Manika, R.Zabels, R.Grants, K.Schwartz, M.Sorokin. Modification of the structure and nano-mechanical properties of LiF crystals under irradiation with swift heavy ions, Program and Materials, Wo-1, p.12.

International conference "Advanced Carbon Nanostructures" (ACN'2011), July 4-8, 2011, St.Petersburg, Russia

8. I.Manika, J. Maniks, R. Zabels, J. Gabrusenoks, M. Krause, M. Tomut, K. Schwartz, Nanoindentation and Raman spectroscopy study of graphite irradiated with swift 238U ions. International conference "Advanced Carbon Nanostructures", St.Petersburg, Russia, 2011, July 4-8, Book of Abstracts, p.334.

9th Intern.Sci.and Tech. Conf. Advanced metal materials and technologies (AMMT’2011), June 22–24, 2011, St Petersburg

9. V.Sursajeva, F.Muktepavela. Effect of the first order different edges on the motion of grain boundaries in Zn., Russia Proc. 400-401p.(stenda) 27th Scientific conference of the ISSP, February 14-16, 2011, Riga, Latvia

10. R. Zabels, F.Muktepavela, L.Grigorjeva, K.Kundziņš, E.Tamanis. Obtaining of ZnO nanocrystallites via oxidation of Zn powder. Abstracts p.27.

11. R.Grants, R.Zabels, I.Manika AFM and nanoindentation study on LiF crystals irradiated with swift Kr ions. Abstracts p.28.

–  –  –

Research Area and Main Problems The Department includes two research groups – the Laboratory of nuclear reactions and Laboratory of Transition Metals Compaunds Physics. The following main investigations are

developed in the department:

- experimental and theoretical investigation of nuclear structure at medium and high excitation energies;

- development of the nuclear spectroscopy methods for the identification of radioactivity and nuclear materials in Latvia;

- development of gamma spectrometric methods for investigation of radionuclides, their migration in the environment, soils and ground waters in the most potentially polluted regions of Latvia;

- application of the liquid scintillation methods for the monitoring of tritium content in environment and drinking waters of food industry;

- EPR, FTIR, RAMAN and optical spectroscopies study of human blood after irradiation

- magnetic ions exchange interaction in the antiferromagnetic oxides MeO-MgO solid solutions were studied using of optical absorption, luminescence, EPR and Raman spectroscopies

- exchange interaction between radiation defects and transition metals ions in the dielectric crystals doped with the transition metals ions

International projects:

Participation in the project „Investigation of nuclear structure via (n,γ), (d,p) and (d,t) nuclear reactions” with Institute of Nuclear Physik (Rzez, Czech Republic), Technical University Munich, Institute Laue -Langevin (Grenoble, France).

Scientific Staff:

Dr.hab. J.Berzin Dr.hab. M.Balodis Dr.hab. V.Bondarenko Dr.hab. N.Mironova - Ulmane Dr. L.Simonova Dr. T. Krasta Dr. D.Riekstina Dr. V.Skvortsova Dr. O.Veveris Dr.Ing.sc. A.Pavlenko Mag. Sc. M.Polakovs Dr. J. Proskurins

Technical Staff :

S.Afanasjeva

Students:

Mag. students K. Bavrins

–  –  –

Dr. hab. J. Berzins, European Commission Euratom, Brussels,Belgium (8 days), 2011.

Dr. hab. J. Berzins, Cyclotron Workshop, Ispra, Italy 28-29 November 2011.

Dr. hab. J. Berzins, Insitut Laue Lagevin, Grenoble, 2-5 February 2011.

Dr. hab. J. Berzins, Insitut Laue Lagevin, Grenoble, 5-13 December 2011.

N.Mironova-Ulmane, Institute of Physics Tartu Estonia (3 week) N.Mironova-Ulmane Sweden (1week) N.Mironova-Ulmane, Coimbra, Portugal (1week) M..Polakovs Coimbra, Portugal (1week) N.Mironova-Ulmane Minsk, Belarus (1week) V. Skvortsova., Minsk, Belarus(1week) A.Pavlenko IAEA Wiena,Austria (10 mounth)

Cooperation

Latvia

1. Stradina university of Latvia (Dr. hab., Prof. M.Eglite, Dr.T.Zvagule).

2. Radiation Safety Center.



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