The Laboratory was born in 1992. Stuff of Lab is 15 positions today. Lab. Leaders are Prof. S.Kukushkin, Dr.of Science A. Osipov, Dr. of Science E. Kalashnikov. They are formed the sientific core of Lab. in field of FIRST ORDER PHASE TRANSITION IN CONDENSED MEDIA . Film growth, melt crystallization, pore formation, material destruction are the topics of Lab researchers.

 JOINTED SCIENTISTS

 Post-Graduate Students:

The Main Laboratory Activities

The basic directions of the Lab. activities in the field of fundamental studies can be conditionally sectioned: FOPT in one-component system and FORT in multi-component systems.

The Lab leads theoretical studies on the thermodynamics of one -component multiphase systems and kinetics of inter-phase transitions [1-4]. One of the most important achievements is the development of phenomenological theory of the phase diagrams describing of any one-component system [5]. This theory is followed by a comprehensive presentation of the phase transition between phases with different degree of the ordering. The example is gas-crystal or liquid-crystal systems with the ordering in the new phase nuclei. Another important fundamental result has achieved in the strict theory of disturbances of the FOPT kinetics [6] which allows an analytical calculations of any phase transition parameters such as the supersaturation of new phase nuclei concentration, the size distribution, the nucleation rate etc in terms of time. Also, the number of new approaches and methods for investigation of FOPT individual stages have developed.
Specifically, the theory of soliton mechanism of new phase island migration [7], the theory of heteroepitaxial growth of crystals and non-linear waves which occur in the FOPT process [8], the theory of morphological stability of islands [8], continuum theory of film growth [9] have been studied.
FOPT in multicomponent systems supposes the general method of phase transitions studies in multicomponent systems. The classification of all processes is possible [10]. A self-sustained oscillations at crystallization have been predicted theoretically [12]. These oscillations is confirmed by experimental data [11]. The theory of self-organization in multicomponent crystallizing systems has been developed [12]. It is suggested new theory relating an evolution of phase composition with an evolution of different properties of the film [13]. Solid solutions and eutectic systems are studied in the framework spinodal decomposition, decomposition of metastables states.

Film growth

Film growth takes the most important part of Lab activities.

Formation on the surface of nuclei from supersaturated vapour or liquid as the film growth from supersaturated medium which can be one-component or multi-component has investigated in [1, 2, 10]. The component interaction is accounted. Independent growth of nuclei from supersaturated vapor or liquid is the topic of LAB's activity also. Particle coarsening (island) or Ostwald ripening features the formation of generalized temperature and diffusion fields. Islands with size below the critical one dissolve while those with a size exceeding the critical one become larger. In the kinetic process the total number of islands is reduced and certain distribution of islands and phase composition (for multicomponent system) is established. This stage is the most protracted and the final formation of the film structure takes place as it has been demonstrated in the whole number of our experimental and theoretical papers [2, 13, 19-24].

Merging of new phase island into continuous film has reviewed by great variety of methods of film growing and the investigation results in derivation of growing film characteristics which can be confirmed in the course of experiment such as island size distribution function, mean size, number of islands in each growing phase.

Ion-plasma deposition.

Our researches are not constrained by theoretical studies of IPD films but include experimental verification of predicted phenomena. Joined research with St.Petersburg Electrical Engineering University are dedicated to making technology of high temperature superconductor films (HTS).S.A.Kukushkin and A.V.Osipov in their paper [12] had supposed the self-organization at nuclei formation and then it was discovered for HTS film growing [11].

 Molecular Beam Epitaxy (MBE).

The processes of film growth by MBE method are described in [1, 2, and 14]. Nucleation from one-component vapours as well as from multi-component one [10] were examined. Mechanisms of growing of one-component, binary and multicomponent films at the stage of Ostwald ripening have been considered. An influence of matter sources and rate of substrate cooling on the film structure have been analysed. The procedure of determination of heat-mass transport mechanism for the particular system has been developed.
There have been revealed deposition conditions in which specified film structure is produced [1, 2, 10, 12, and 14].
All results mentioned above were tested on different systems such as TiN [1, 2] and their pinpoint accuracy has been proved.

Liquid epitaxy method.

The theory of growth of single component films from a melt, and theory of nucleation and Ostwald ripening for binary and multicomponent films [13,20-22] have been developed. The features of growing of eutectic composition films has been investigated [25,26] S. Kukushkin suggested the method of relaxation liquid phase epitaxy [23]. This was recognised the best work on physics of diffusion processes in 1990.

This important method is difficult for theoretical estimation since the flux of active component from carrier gas on the substrate is non-uniform over the area that leads to concentration gradients causing the difference in film properties over the surfaces. Recently S.A.Kukushkin and D. Grigoriev developed the approach to these problems and obtained equations describing the film properties depending on the distance from the substrate edge and process parameters [25,26].

 PAPERS

1. S.A. Kukushkin, A.V. Osipov, New Phase Formation on Solid Surfaces and Thin Film Condensation. Progress in Surface Science. 1996, V. 51, N 1, P.1-107.
2. Kukushkin S.A., Slyozov V.V. Disperse systems on the surface of solids.(Evolution approach): Mechanisms of thin film formation. St. Petersburg. Nauka. 1996. 309 pp. (In Russian).
3. S.A.Kukushkin, A.V. Osipov. Kinetics of the initial stage in a first-order phase transformation in thin Films. Phys. Solid State. 1997. V.39. N1. P.104-108.
4. A.V. Osipov, Kinetic model of vapour-deposited thin film condensation: nucleation stage. Thin Solid Films. 1993. V.227. P.111-118.
5. A.V. Osipov, A continuum model for thin-film condensation, J. Phys. D: Appl. Phys. 1995. V.28. N7. P.932-941.
6. Kukushkin, A.V. Osipov. Perturbation theory in the kinetics of first-order phase transitions. J. Chem. Phys. 1997. V.107.N8. P.3247-3252.
7. S.A.Kukushlin, A.V.Osipov, Soliton model of island migration in thin films. Surf. Sci. 1995. V.329. N1/2. P.135-140.
8. S.A.Kukushkin, A.V. Osipov, Microscopic theory of epitaxial growth on vicinal surface. Thin Solid Films. 1993. V.227. P.119-127.
9. S.A.Kukushkin, A.V. Osipov, Morphological stability of islands under first-order phase transitions. Phys. Rev. E. 1996. V.53.N3. P. 521-525.
10. S.A. Kukushkin, A.V. Osipov, Nucleation kinetics of thin films a multicomponent vapour. J.Phys.Chem. Solid. 1995. V56.N6. P.831-838
11. E.K. Gol'man, V.I.Gol'drin, S.A. Kukushkin, A.V. Osipov, D.A. Plotkin, S.V. Razumov, Self-organization in film nucleation in the high-T_c superconductor Y-Ba-Cu-O system.Phys. Solid State. 1997. V.39. N2. P.189-191.
12. S.A. Kukushkin, A.V. Osipov , Self-organization in the process of multicomponent film nucleation. J. Phys. Chem. Solids 1997. V.58. N7. P.1115-1118.
13. S.A. Kukushkin. Evolution processes in multicomponent and multiphase film growth from solutions. Thin Solid Films, 1994, V.239. P.16-26.
14. S.A. Kukushkin, Evolution processes in multicomponent and multiphase films. Thin Solid Films, 1992, V.207. P.302-312.
15. S.A. Kukushkin, T.V.Sakalo, Diffusional coalescence of island films on the crystal surface in the case of layer-by-layer growth of island -1 an isolated system. Acta metall.mater.1993. V.41. N4.P.1237-1241.
16. S.A. Kukushkin, T.V.Sakalo, Diffusional coalescence of island films on the crystal surface in the case of layer-by-layer growth of island -2 an open system. Undamped sources of deposited atoms Acta metall.mater.1993. V.41. N4.P.1243-1244.
17. S.A. Kukushkin, T.V.Sakalo, Diffusion coalescence of island films on the crystal surface in the case of layer-by-layer growth of island -3 .Analysis of the model. Acta metall.mater.1994. V.42. N8 P.2797-2801. T.V.Sakalo,
18. T.V.Sakalo, S.A. Kukushkin, Diffusional coalescence of island films on the crystal surface in the case of layer-by-layer growth of island -4 .Theory and experiment. Acta metall.mater.1994. V.42. N8 P.2803-2810.
19. S.A. Kukushkin, Evolution processes in island films grown from single -component melts: lasts stage. J. Phys. Chem. Solids .1994. V55. N8. P.779-785.
20. S.A. Kukushkin, V.V. Slezov, Growth of island films from binary melts or vapor phase at the Ostwald ripening stage under non-isothermal conditions. J. Phys. Chem. Solids .1996. V56. N8. P.601-614.
21. S.A. Kukushkin, Evolution processes in ensembles of disperse particles on the surfaces of solids. Mechanisms of initial stages of formation of thin multicomponent films. 1. Coservative systems. Phys.Solid State .1993. V.35. N6. P.797-804.
22. S.A. Kukushkin, Evolution processes in ensembles of disperse particles on the surfaces of solids. Mechanisms of initial stages of formation of thin multicomponent films.Open systems . Phys.Solid State .1993. V.35. N6. P.797-804.
23. V.N.Bessolov, S.A.Kukushkin, M.V.Lebedev, and B.V.Tsarenkov, Relaxation liquid phase epitaxy based on reversal of the mass transport and its potential for making layers of III-V materials. Sov.Phys.Tech.Phys. 1988. V.33. N5 .P.902-905.
24. S.A. Kukushkin, A.V. Osipov. Nucleation kinetics of one-component films grown from melts or fluxes. Tech. Phys. 1995. V.40. N6. P.615-618.
25. S.A. Kukushkin, D.A.Grigoriev, . Theory of late-stage island films growth from eutectic melts.//Growth of crystal. 1998 . 27. P.32-41.
26. S.A. Kukushkin, D.A. Grigoriev. Theory of late-stage island films growth from eutectic composition melts. Growth of Crystals, 104-112 .1999

This field is comprehensively covered in [1, 2, 3]. As it is known, melts crystallization in the same manner as film grows proceeds through nucleation, independent growth and Ostwald ripening. It should be noted that S.Kukushkin discovered Ostwald ripening in one-component melts for the first time in 1985 [4] and then, this theory was generalized to binar and multi-component melts [5-10]. There works deal with influence of heat stock on the structure of resultant cast.

The formation of casts from eutectic composition melts is reviewed in [11]. Non-uniformity of structure and phase constitution of cast during their crystallization on layer by layer mechanism involve some problems. In [12] this problem is solved for one-component melts as well as to binar and multi-component ones and all characteristics of final cast in terms of its length are obtained.

 
PAPERS

1. S.A. Kukushkin, Theory of the Ostwald ripening of new-phase nuclei in single-component melts. Acta Met. Mater. 1994. V.43. P.715-722.
2. A.V. Osipov, Kinetics of bulk crystallization of a melt in its initial state. Phys. Solid State. 1994. V.36. N5. P.664-671.
3. V.V Slezov ,S.A. Kukushkin, Nucleation of solid phase in supercooled melts Phys. Solid State. 1996. V.38. № 2. P.239-243.
4. S.A. Kukushkin. Kinetcs of crystallization of one-component melts. Sov.Phys. Solid State. 1985. V.27. № 10. P.1794-1796.
5. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and precipitation of supersaturated solid solutions under nonisothermal conditions. Sov.Phys. Solid State. 1987. V.29. N12. P.2092-2097.
6. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and precipitation of supersaturated solid solutions containing sinks and sources of heat and matter Sov.Phys. Solid State. 1988. V.30. N11. P.1858-1860.
7. S.A. Kukushkin, T.V. Sakalo. Evolution of diffusion coalescence of solid solutions and of temperature coalescence of one-component melts in the case of layer-by-layer growth of nuclei of a new phase. . Sov.Phys. Solid State. 1992. V.34. N4. P.587-590.
8. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and decay of supersaturated solid solutions at the Ostwald ripening stage under non-isothermal conditions. J. Phys. Chem. Solids .1995. V.56. N9. P.1259-1269.
9. S.A. Kukushkin, V.V Slezov Theory of the Ostwald ripening in multicomponent systems under non-isothermal conditions. J. Phys. Chem. Solids .1996. V.57. N2. P.195-204
10. S.A. Kukushkin, A.V. Osipov. Nucleation kinetics of one-component films grown from melts or fluxes. Tech. Phys. 1995. V.40. N6. P.615-618.
11. Kukushkin S.A., Grigor'ev D.A. Theory of late-stage crystallization of eutectic melts Phys. Solid State. 1996. V.38. N4. P.698-702.

Fundamental results gained at phase transition studies are used for the description of decomposition of supersaturated solid solutions [1-7]. The special attention is paid to the latest stage of multicomponent, evolution of its chemical composition. The most impressive results are achieved at studies of SSS decomposition under non-isothermal conditions [1, 2, 4, and 5]. Also, spinodal and eutectic decomposition of solid solution breakdown under non-isothermal conditions [1, 2, 4, and 5].

1. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and precipitation of supersaturated solid solutions containing sinks and sources of heat and matter Sov.Phys. Solid State. 1988. V.30. N11. P.1858-1860.
2. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and precipitation of supersaturated solid solutions under nonisothermal conditions. Sov.Phys. Solid State. 1987. V.29. N12. P.2092-2097.
3. S.A. Kukushkin, T.V. Sakalo. Evolution of diffusion coalescence of solid solutions and of temperature coalescence of one-component melts in the case of layer-by-layer growth of nuclei of a new phase. Sov.Phys. Solid State. 1992. V.34. N4. P.587-59.
4. S.A. Kukushkin, V.V Slezov. Crystallization of binary melts and decay of supersaturated solid solutions at the Ostwald ripening stage under non-isothermal conditions. J. Phys. Chem. Solids .1995. V.56. N9. P.1259-1269.
5. S.A. Kukushkin, V.V Slezov Theory of the Ostwald ripening in multicomponent systems under non-isothermal conditions. J. Phys. Chem. Solids .1996. V.57. N2. P.195-204.
6. Kukushkin S.A., Grigor'ev D.A. Theory of late-stage crystallization of eutectic melts Phys. Solid State. 1996. V.38. N4. P.698-702.
7. S.A. Kukushkin, A.V. Osipov. Evolution of phase composition and associated properties in the process of growth of thin films (1999). J. of Applied Physics v.86 N3 .1370-1376.

Formation and growth of pores in solids are essential for strength theory of materials and structures. The studies of origination and evolutions of pores on exposure to ionizing radiation are particular importance. The lab is in progress theoretical and experimental examinations of Ostwald ripening of pores under radiation action [1,2]. A microcrack presentation as a crystal dendrite has followed to the model of kinetics of crack growth from initial pore[3].

1.Shapurko A.V., Kukushkin S.A. The Evolution of vacancy porosity in Alkali Haline single crystals . J. Phys. Chem. Solids. 1992.V.53. N6. P.841-845.

2.Shapurko A.V., Gromov L.A. , Kukushkin S.A., V.I. Shtan"ko. Diffusion growth of vacancy pores in irradiated cesium bromide single crystals. Sov.Phys. Solid State. 1988. V.30. N11. P.2007-2008.

3.Anna Vakulenko, Serge Kukushkin, Kinetics of brittle fracture of elastic materials (1998), J. Physics of the Solid State, V.40, N7, 1147-1150

Our contacts

We have common research with Moscow State University, A.F. Ioffe Physico-Technical Institute , St.-Petersburg State University, St.-Petersburg Electrotechnical University, S.-Petersburg Technological University (Technological Institute), Khar'kov National Science Center (Khar'kov Physic-Technical Institute).

Experimental verification Lab. theoretical results and interchanges of data are interesting for Lab. in the framework of the film growth, melt crystallisation, decomposition of solid solution.

Vakulenko's support. Last updated 11.11.1999.