The surface morphology of nanosized copper and nickel films on mica has been studied on a scanning tunneling microscope. The height parameters and fractal dimension of the copper and nickel films of different thicknesses have been determined. Characteristic sizes of structural agglomerates for the copper and nickel films as functions of their thickness are reported. The choice of film thickness and synthesis conditions makes it possible to formulate recommendations for the development of technology for growing structures with a specified surface morphology.
Some patterns of formation of the fractal relief of nanosized molybdenum films on the mica surface are considered using the atomic force microscopy. The tools and techniques for post-processing and analyzing 2D images acquired through this specific research methodology have been thoroughly investigated. The significance of the contributions of errors and uncertainties to the final outcome of the acquired data is discussed. Additionally, a threshold detection method was applied to analyze the fractal dimension, allowing for the identification of areas of interest and exclusion of noise components, as well as regions not having scientific significance. The fractal dimension of the obtained agglomerates was determined at various scales, ranging from 0,5 to 3 mu m. The next value D-c = 2,19 and D-c = 2,45 were obtained for the original images; D-c = 2,13 and D-c = 2,45, respectively, for the images processed using the threshold detection method. The obtained data provide prospects for further research and development of novel methods for synthesizing materials with specific properties.
The morphology of the relief of nanosized titanium films on the mica surface was studied using a scanning probe microscope at various scales. The characteristic features of the nanorelief of the surface of the investigated films, including fractal properties, are described. The obtained data on the fractal dimension are compared with the available experimental data, as well as the data obtained using scanning tunneling microscopy. Recommendations for the development of technology for «growing» structures with a given surface morphology are proposed.
Results are presented from an analysis of the nano- and magnetic domain structures of high coercive Sm(CoCuFe)5 alloy using fractal geometry. Fractal dimension Df of the nano- and domain structures are determined at different stages of heat treatment. It is shown that Df ~ 2.08 corresponds to the nanostructure of samples with a coercive force of 7 kOe, while Df ~ 2.3 corresponds to the nanostructure of samples with a coercive force of 32 kOe.
Методом атомно-силовой микроскопии получены изображения наноструктры составляющих гетерогенного интерметаллида SmCoCuFeZr в высококоэрцитивном состоянии. На микроуровне в сплавах выделили два типа областей (фазовых составляющих) отличающихся по интегральному элементному составу и интервалам коэрцитивности. На основе данных атомно-силового микроскопа проводится анализ фрактальных характеристик поверхности этих областей. Показано, что фрактальная размерность наноструктуры коррелирует с локальной коэрцитивностью фазовых составляющих. Фазовая составляющая с относительно низкой коэрцитивностью демонстрирует возможность существования структур с фрактальной размерностью в диапазоне 2,396 - 2,475, что соответствует умеренно развитому фрактальному рельефу. При этом высококоэрцитивная составляющая с регулярной наноструктурой характеризуется более высокой фрактальной размерностью 2,452 - 2,508, а на отдельных участках образца встречались области с фрактальной размерностью до 2,577 . The atomic force microscopy was used to obtain images of the nanostructure of components of a heterogeneous intermetallic SmCoCuFeZr compound in a highly coercive state. At the microlevel, two types of regions were distinguished in the alloys, differing in integral elemental composition and coercivity intervals. Based on the atomic force microscopy data, an analysis of the fractal characteristics of the surface is carried out on both of the above types of areas. It is shown that the fractal dimension of the nanostructure correlates with the local coercivity of the phase components. The phase component with a relatively low coercivity demonstrates the possibility of the existence of structures with fractal dimensions in the 2,396 - 2,475 range corresponding to a moderately developed fractal relief. In this case, the high-coercive component with a regular nanostructure is characterized by a higher fractal dimension of 2,452 - 2,508, and in some areas of the sample there were regions with a fractal dimension up to the value of 2,577.
В данной работе методом молекулярной динамики с использованием потенциала сильной связи проведено моделирование процесса молекулярно-лучевой эпитаксии с целью определения закономерностей при формировании фрактальных металлических пленок платины на поверхности родия. Установлена возможность формирования фрактальных структур как в островковых пленках платины на поверхности родия, так и в сплошной пленке. Установлены параметры компьютерного эксперимента, определяющие переход от отдельных островковых пленок к сплошной пленке в указанной системе. С использованием различных программных продуктов Gwyddion и Image Analysis, а также собственной разработки FractalSurface проанализирован диапазон изменения фрактальной размерности при различных условиях молекулярно-динамического эксперимента методом подсчета кубов. Полученные значения фрактальной размерности в целом находятся в приемлемом согласии между собой, однако существует ряд исключений, которые обсуждаются более подробно. Сравнительный анализ получаемых результатов позволяет формулировать рекомендации для методики создания, корректировки и прецизионного контроля при «выращивании» структур с заданной морфологией поверхности. In this work, the molecular dynamics method and the tight-binding potential are used to simulate the process of molecular beam epitaxy in order to determine the regularities in the formation of fractal platinum metal films on the rhodium surface. The possibility of formation of fractal structures both in island platinum films on the rhodium surface and in a continuous film has been established. The parameters of the computer experiment, which determine the transition from individual island films to a continuous film in the indicated system, have been established. Using various software products Gwyddion and Image Analysis, as well as our own software FractalSurface, the range of changes in the fractal dimension has been analyzed under various conditions of a molecular dynamics experiment by the method of cube counting. The obtained values of the fractal dimension are generally in acceptable agreement with each other; however, there is a number of exceptions, which are discussed in more detail. A comparative analysis of the results obtained allows one to formulate recommendations for the methodology for creating, adjusting and precision control when «growing» structures with a given surface morphology.
The results of the micro- and nanostructures investigation of Sm(CoCuFe) 5 alloys by means of scanning electron and atomic force microscopy are presented. It was shown that sequential high- and low-temperature heat treatments lead to the formation of a homogeneous microstructure with nanoscale compositional heterogeneities. Such a structure provides a coercive filed of up to 32 kOe. The coercivity and remanent magnetization of the samples in the temperature range from 300 to 700 K linearly decrease. The predominant coercivity mechanism in these materials is pinning on nanoscale inhomogeneities with an increased copper concentration. The fractal dimension of the surface of the Sm(CoCuFe) 5 alloy metallographic specimen was determined at different stages of heat treatments. The comparative analysis of magnetic properties and microstructure in the framework of fractal geometry was carried out.
A scanning tunneling microscope has examined morphology of the relief of copper films obtained by thermal vacuum deposition on the surface of mica. The characteristic features of the nanorelief of the film surface, including fractal properties, are described.
A comparative investigation of the current-voltage characteristics of the gold and silver film samples with tungsten tip proves that experimental results demonstrate the need for careful analysis of the parameters affecting the tunneling current to receive additional information about the electronic structure of the sample.
As a result of our investigation, it was shown that of thin metal films on dielectric substrates allow to prepare samples that satisfy the requirements for working the scanning probe microscope in scanning tunneling microscope mode. This preserves the information about the features of the surface morphology of individual objects smaller than 100 nm. The sample «silver/mica» is considered as an example. Linear dimensions of individual surface objects (peaks and troughs) have been determined including the factors affecting the formation of relief pattern. Certain parts of the profile and surface have been investigated for the presence of fractal structures. It was found that the system of clusters on the surface of the investigated sample is fractal. In addition, for each cluster dependence of the natural logarithm of the number of particles on the natural logarithm of the particle size of the cluster is approximately linear, that allows to consider the structure of individual clusters and the surface profile as fractal. The investigation of the current-voltage characteristics of the metal-metal silver sample with tungsten tip proves the experimental results demonstrating the need for careful analysis of the parameters affecting the tunneling current to receive extract information about the electronic structure of the sample.