Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (11)
Material
Years
Year
  • 1
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The nucleation and growth of islands of a new phase on the surface of solids has been studied both experimentally and theoretically for the particular case of the transition from the pyrochlore to perovskite phase in a thin film of a lead zirconate-titanate ferroelectric. This transformation was chosen because the new-phase islands have a stable circular shape in this case, a relatively large size (10−5–10−4 m) permitting their observation with an optical microscope, and a low growth rate (10−8–10−9 m/s). A theoretical analysis of the process, based on the kinetic theory of first-order phase transitions proposed earlier, has been carried out and the behavior in time of all main characteristics of a phase transformation, namely, nucleation rate, concentration of the new-phase islands, their size distribution, and relative overheating, has been calculated. The same characteristics have been measured experimentally, thus permitting one for the first time to make a thorough comparison of the theoretical with experimental data on the kinetics of first-order phase transitions. They have been found to be in a good agreement.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The process of new-phase nucleation in the YBa2Cu3O7−x system deposited by magnetron sputtering has been studied. The first experimental observation of the phenomenon of temporal self-organization in the course of new-phase formation, which was predicted theoretically,1–3 is reported. Auto-oscillations in the number of nuclei of various chemical compounds 20–60 nm in size were observed to occur within the 15 to 300-s time interval, the total number of nuclei varying aperiodically from 1013 m−2 to less than 1011 m−2.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Physics of the solid state 39 (1997), S. 1299-1304 
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Kinetics of self-consistent growth of new-phase nuclei from eutectic melts have been studied. The growth kinetics of nuclei of eutectic composition are shown to depend on the sum of supersaturations over all components. It has been established that nuclei in a eutectic melt reach a common critical radius determined by supersaturation for both components. The concept of a diffusion dipole is introduced: a two-phase object in a eutectic melt or solid solution, in which two nuclei of different composition are related through a common diffusion field. The morphological stability of such dipoles is studied. It is found that a nucleus of eutectic composition is more stable with respect to small fluctuations in its shape than the corresponding one-component nucleus. It is shown that perturbations resulting in dipole-shape distortions develop perpendicular to the axis connecting the centers of the nuclei of different compositions (i.e. the dipole axis). This is consistent with the well-known experimental observation of the layered structure of eutectic compositions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Physics of the solid state 40 (1998), S. 1147-1150 
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A phenomenological model is proposed for the evolution of microcavities in materials under load based on a study of the kinetics of brittle fracture in a linearly elastic deformable medium containing a microcavity. The basic principle of the model is that, during deformation of a material containing a micropore, fluctuations of its shape occur. The surface tension at the micropore-medium interface stabilizes these fluctuations but if the load exceeds a critical value, these fluctuations may begin to evolve. In so doing, they distort the shape of the microcavity. These fluctuations are none other than cracks. This concept of crack growth and their nature has a close analogy with the evolution of dendrites formed in supercooled melts as a result of the loss of stable crystal shape. An analysis is made of the laws governing the evolution of a microcavity and local loss of shape stability under steady-state pressure for the case of a sphere containing a quasispherical cavity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Physics of the solid state 40 (1998), S. 1467-1469 
    ISSN: 1063-7834
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study is made of the dynamics of self-consistent motion and growth of spherical new-phase nuclei from a eutectic melt. The growth rate of nuclei is shown to be proportional to supersaturation in both components. Motion of a single nucleus in a concentration-gradient field and of a pair of nuclei in a self-consistent concentration field is investigated. The velocity of motion of the nucleus as a whole has been established to depend on the key parameters of the problem, namely, supersaturation, radii of the nuclei, and their separation. The force of mutual attraction between nuclei is estimated, and it is shown to be inversely proportional to the fifth power of their separation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 1201-1208 
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We construct an asymptotic theory that describes the kinetics of first-order phase transitions. The theory is a considerable refinement of the well-known Lifshits-Slezov theory. The main difference between the two is that the Lifshits—Slezov theory uses for the first integral of the kinetic equation an approximate solution of the characteristic equation, which is valid in the entire range of sizes except for the blocking point, i.e., it uses a nonuniformly applicable approximation. At the same time, the behavior of the characteristic solution near the blocking point determines the asymptotic behavior of the size distribution function of the nuclei for the new phase. Our theory uses a uniformly applicable solution of the characteristic equation, a solution valid at long times over the entire range of sizes. This solution is used to find the asymptotic behavior of all basic properties of first-order phase transitions: the size distribution function, the average nucleus size, and the nucleus density.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 1370-1376 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A complete set of equations describing the evolution of phase composition of an island ensemble at the stage of the Ostwald ripening in the process of thin-film growth is derived and its solution is found. The size distribution function of islands in solid solutions is obtained for different types of growth mechanisms. The general approach to control phase composition and associated properties (electric, optical, mechanical, and others) in formed multicomponent systems is elaborated. It is shown that the most favorable conditions to control these properties occur at the Ostwald ripening stage and also during nonlinear phenomena, such as self-excited oscillations or self-organization. The relationship between size and composition of the new phase nuclei formed in the course of condensation of solid solution films is revealed. A set of equations describing the evolution of the size distribution function of the properties in island films of solid solutions during changes in external parameters of the system is derived and solved. We show that substantial dependence of composition on external parameters is revealed for the sizes of islands with radius R≤10−8 m, irrespective of the type of substance. For island-type films of stoichiometric composition, the diagram for coexistence of appropriate properties is plotted in the concentration-temperature coordinates that allows to us determine the conditions required to obtain the properties. Probable periodic changes in time and space of various properties on multicomponent systems undergoing the first order phase transition are predicted. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Technical physics 43 (1998), S. 846-852 
    ISSN: 1090-6525
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The initial stages of growth of films and coatings by chemical vapor deposition are investigated. A system of equations is derived which describes the evolution of an island film at the stage of Ostwald ripening under conditions characteristic of vapor deposition. Solving this system of equations yields the dependence of all of the main characteristics of island films (the size distribution function of the islands, the dependence of the mean radius and density of the islands) as functions of time and the spatial coordinate. Suggestions are given for the preparation of films with prescribed properties.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1090-6525
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A model system describing the nucleation of films from a multicomponent vapor with allowance for chemical reactions between different components in the initial phase is investigated in detail. It is shown that the condensation of thin films can proceed by different avenues, depending on the values of external parameters such as the temperature or the precipitation rate of particles of the component that limits the chemical reaction. In particular, low precipitation rates are characterized by a stable condensation regime, in which any deviations from equilibrium die out. At medium precipitation rates the phase transition takes place in a self-excited oscillatory regime corresponding to a stable limit cycle. Finally, at high precipitation rates the stable limit cycle breaks up, and the new phase usually condenses in a sawtooth (accretion) regime. A procedure is developed for controlling the given oscillatory processing by judicious time variation of the external parameters. The investigated system is found to have a special kind of memory in that for external parameters with identical values but different histories the films condense differently; even a slight difference in the past behavior of the external parameters can lead to different precipitation regimes. It is concluded that these memory effects are in fact responsible for the poor reproducibility encountered in some cases of experiments on film growth utilizing chemical reactions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Technical physics 42 (1997), S. 1212-1219 
    ISSN: 1090-6525
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A complete system of equations describing the evolution of the phase composition of islands in the Ostwald ripening stage during the growth of thin films is derived and a solution is found. The distribution function of islands of solid solutions is obtained for different growth mechanisms. A general approach to controlling the phase composition and associated properties (electrical, optical, strength, and so on) in the multicomponent systems formed is developed. The investigation is conducted for the example of thin multicomponent films. It is shown that the greatest possibilities for controlling these properties are at the Ostwald ripening stage and in the presence of nonlinear phenomena such as self-oscillation or self-organization. A relation is found between the size and composition of the new-phase nuclei which form during the condensation of films of solid solutions. A system of equations describing the evolution of the distribution function of properties in island films of solid solutions as a function of the external parameters of the system is derived and solved. It is shown that a strong dependence of the composition on the external parameters appears for islands with radius R⩽10−8 m, irrespective of the type of material. A diagram of the coexistence of the corresponding properties in concentration-temperature coordinates is constructed for island films of stoichiometric compounds; this makes it possible to determine the necessary conditions for obtaining such films. It is predicted that various properties in multicomponent systems which undergo a first-order phase transition can vary periodically in time and space.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...