Fractal-Stereometric Correlation of Nanoscale Spatial Patterns of GdMnO3 Thin Films Deposited by Spin Coating

Abstract

Multiferroic systems are of great interest for technological applications. To improve the fabrication of thin films, stereometric and fractal analysis of surface morphology have been extensively performed to understand the influence of physical parameters on the quality of spatial patterns. In this work, GaMnO3 was synthesized and thin films were deposited on Pt(111)/TiO2/SiO2/Si substrates using a spin coating apparatus to study the correlation between their stereometric and fractal parameters. All films were studied by X-ray diffraction (XRD), where the structure and microstructure of the film sintered at 850 °C was investigated by Rietveld refinement. Topographic maps of the films were obtained using an atomic force microscope (AFM) in tapping mode. The results show that the film sintered at 850 °C exhibited a clear formation of a GdMnO3 orthorhombic structure with crystallite size of ~14 nm and a microstrain higher than other values reported in the literature. Its surface morphology presented a rougher topography, which was confirmed by the height parameters. Topographic differences due to different asymmetries and shapes of the height distributions between the films were observed. Specific stereometric parameters also showed differences in the morphology and microtexture of the films. Qualitative rendering obtained by commercial image processing software revealed substantial differences between the microtextures of the films. Fractal and advanced fractal parameters showed that the film sintered at 850 °C had greater spatial complexity, which was due to their higher topographic roughness, lower surface percolation and greater topographic uniformity, being dominated by low dominant special frequencies. Our combination of stereometric and fractal measurements can be useful to improve the fabrication process by optimizing spatial patterns as a function of the sintering temperature of the film.

Morphological and multifractal properties of Cr thin films deposited onto different substrates

“…Related to such a feature, we see in Figure 6b the Hurst coefficient ( Hc ), with average values of 0.521 (BK7), 0.509 (Si), and 0.588 (Glass), is the largest for the Cr film onto Glass sample signaling that its surface tends to display non‐zero correlation that persists over large distances compared to the other samples. In other words, the topography of the film of Cr deposited onto Glass substrate is dominated by lower spatial frequencies (Romaguera‐Barcelay, Ţălu, et al, 2021).…”

“… where dir is liquid entry direction, P 0 ( T ( k )) is occupation percentage, T ( k ) are boxes of equal size T ( n ), PR is occupation pressure, and p c is centroid position ( x , y ). In Figure 6c we see the fractal succolarity (FS) parameter, which is a quantifier of the percolation degree of a topography (de Melo & Conci, 2008; Romaguera‐Barcelay, Ţălu, et al, 2021). The average values found are 0.536 (BK7), 0.512 (Si), and 0.506 (Glass), revealing that the sample deposited onto Glass sample, which have exhibited distinguished features so far, present the smallest FS value.…”

Fractal Analysis on Surface Topography of Thin Films: A Review

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Investigation of deposition temperature effect on spatial patterns of MgF2 thin films

“…A relationship between physical properties and microstructure of formed MgF 2 samples is important in study of material properties modified by applied technological operations. An effective method to The study of the surface spatial complexity of a thin film is a key step in understanding the growth asperity patterns of its surface roughness, and it can be applied to various types of systems, e.g., biological (Astinchap et al, 2022;Matos et al, 2021), polymeric (Ito et al, 2020;Ramazanov et al, 2021), and thin films of various types Dejam et al, 2019;Romaguera-Barcelay, Ţ alu, et al, 2021).…”

“…FL has also been widely used to characterize the surface microtexture of thin films Dejam et al, 2019;Romaguera-Barcelay, Ţ alu, et al, 2021). analysis (p > 0.05).…”