Film Samples Research Articles

Structural and Optical Characterization of Cu2Se0.8S0.2 Thin Films Deposited by Thermal Evaporation

Abstract A simple cost thermal evaporation deposition technique was used to prepare of Cu2SeS thin films on the substrates made of glass at RT with thickness ( 500 + − 20 ) nm . Structural, and optical properties of these films were investigated. The films were structurally characterized using X-ray diffraction XRD analyses, the film samples were morphologically characterized using atomic force microscopy (AFM), and optical UV-Vis spectroscopy was also to characterize the samples. The films have been treated at deferent temperatures (403, 453 &503) K for 1 hour, X-ray diffraction (XRD-with wavelength 1.54 A) study the structure properties of this films suggest a cubic structure and have prominent (111) orientation. AFM analysis, it is evident that Cu2SeS film is polycrystalline in nature, and that crystallite size and average grain size for films after annealing were increasing. The optical absorption coefficient (α) of the film was evaluated using absorbance spectra in the wavelength range (400-1100) nm. The direct band gap of about 2.2 eV, decrease by increasing annealing temperature, The structure and the optical characteristics of these films may have practical applications in renewable energy.

AI-powered precursor quantification in atmospheric pressure plasma jet thin film deposition via optical emission spectroscopy

Abstract This study explores the feasibility of using Optical Emission Spectroscopy (OES) for in situ monitoring of Atmospheric Pressure Plasma Jet systems in the deposition of thin films. We identify process parameters to control film properties by machine learning for data analysis. In experiments, the depth of the carrier gas inlet pipe (pipe depth) is a crucial controllable variable that directly affects the amount of precursor, influencing the film’s thickness, sheet resistance, and resistivity. We collected 96 000 spectra while preparing 12 film samples, subsequently measured the properties of the samples, and analyzed the spectral data using Principal Component Analysis (PCA) and seven supervised machine learning models. A high correlation was found between spectral features and film thickness. We divided the spectral data in a single process based on processing time into the first third (F-third) and the last third (L-third). Using the F-third data, the PCA plot clearly indicated a significant difference between the two pipe depths, achieving a mean recognition accuracy of 95.1% with machine learning models. In contrast, using the L-third data, the PCA plot showed a high degree of overlap between the two pipe depths, resulting in a considerable decline in recognition performance. Overall, it is challenging to distinguish the spectra visually due to variations in precursor amounts and dynamic fluctuations in the OES signals, even after averaging. Nonetheless, through the successful application of machine learning, we demonstrated an effective spectral recognition system for monitoring pipe depth, which aids in the timely control of film properties.

The Influence of Cuprum (II) Acetate (Cu (CH3COO)2) Dopant and Heating Temperature in The Fabrication of Thin Films of Barium Strontium Titanate (Ba0.4Sr0.6TiO3)

Abstract Barium Strontium Titanate (BST), or BaxSr1-xTiO3, is an excellent ferroelectric material that is widely used on thin film applications in microelectronic devices, making BST very essential to the tech industries. This research aims to fabricate Cuprum doped BST thin films at low temperature using the Chemical Solution Deposition (CSD) and spin coating technique, and then to analyze the thin film’s band gap energy from the UV-Vis curve, XRD Spectral and EDAX. The advantage lies in the use of low temperatures in which it allows a significant energy savings compared to other studies. Using the Kubelka-Munk method with the Tauc Plot relation, the bandgap energy values for each BST substrates were obtained. Without Cuprum (II) Acetate dopant, the Band Gap values of the thin film samples are 3.84 eV and 3.77 eV. With 3% concentration of Cuprum (II) Acetate dopant, we obtained smaller Band Gap values, which are 3.74 eV and 3.71 eV. Based on the XRD spectral analysis, the lattice parameters were determined with a tetragonal crystal structure. However, according to the EDAX analysis, the elemental composition obtained is not yet stoichiometric. This research is important to serve as a reference for other researchers and manufacturers to opt into fabrication of thin films with lower energy cost, provide guidance for researchers to have more flexibility in their own thin film fabrication.

Preparation and characterization of smart hydrogels (magnetic field responsive)

Iron nanoparticles were prepared by using the co-precipitation process, and then used to fabricate magnetic field-responsive hydrogel films. The magnetic nanoparticles' structural, physical-chemical, morphological, and magnetic characteristics and the effect of hydrogel films' coating concentration were studied. The properties of the hydrogel film responsive to the magnetic field were investigated using Fourier analysis spectroscopy infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and a vibration sample magnetometer (VSM). The results indicated that all samples showed good inter-integration of the constituent materials and their functional groups. The hydrogel film samples which were polycrystalline, had broad diffraction peaks and showed constant particle size with nearly spherical particles with rounded edges. The SEM image of the magnetic nanoparticles with and without coating was established for the accumulation of numerous nanoparticles with a 17 nm mean diameter. In addition, the magnetic properties of the magnetic field-sensitive hydrogel films were evident and sufficient for drug delivery to the desired location.

Study of the structural and optical properties of pure copper oxide and doped with zinc at fixed weight percentages

Through this research, the effect of doping with zinc ions on the structural and optical properties of copper oxide particles doped with zinc at certain weight percentages was study using Radiofrequency plasma deposition technology. X-ray diffraction (XRD) analyses and field emission scanning electron microscopy were used to ascertain the materials' characteristics. Ultraviolet and visible spectroscopy of pure and doped thin films was also perform to calculate the band gap and electrical conductivity It was discovered using the XRD readings that the pure copper particles saturated with zinc had a crystalline size. It changes as Zn concentration rises and is influenced by the CuO lattice's strain and dislocation density. The thin film samples have structures resembling irregular and cubic grains, as demonstrated by the FE-SEM pictures. After doping with Zn, their homogeneity increases and adopts a regular granular nature. The band gap was also calculated for pure CuO particles as well as those doped with certain percentages of Zn. It was note that the addition of Zn worked to reduce Band gap for CuO

Effect of the deposition temperature on ZnCd(SSe)2 for enhance the efficiency of solar cell application

The photoelectrochemical efficiency of ZnCd(SSe)2 thin films shows a notable enhancement, increasing from 0.08 % to 0.28 %, when deposited at different temperatures (room temperature, 40 °C, 50 °C, and 60 °C). This study aims to develop ZnCd(SSe)2 thin films using a cost-effective single-step process called the Arrested Precipitation Technique (APT). This study demonstrates that varying the deposition temperatures significantly impacts the optical, structural, and morphological properties of the resulting thin films. Optical analysis shows a reduction in the optical energy band gap from 1.92 to 1.63 eV as the bath temperature increases. X-ray diffraction confirms the formation of nanocrystalline thin film samples with improved crystallinity, as indicated by the increased intensity of the (100) diffraction peak. Scanning electron microscopy reveals changes in surface morphology corresponding to different deposition temperatures. The thin films exhibit polycrystalline characteristics, as verified by transmission electron microscopy and selected area electron diffraction pattern analysis. Energy Dispersive Spectroscopy analysis identifies the presence of Cd, Zn, S, and Se elements with near-ideal stoichiometry, suggesting a favorable composition. Importantly, the photoelectrochemical performance increases significantly from 0.08 % to 0.28 % with rising deposition temperature, marking a substantial improvement with potential for further investigation and development in the field.

Analysis of forensic polymer samples using double shot pyrolysis gas chromatography – Mass spectrometry

Polymers are present in many different products, such as paints, plastics, and rubbers, which are routinely encountered in forensic casework. Comparison of such samples involves an initial visual examination followed by comparison of the chemical compositions of the exhibits. Techniques such as Fourier transform infrared spectroscopy (FTIR) and pyrolysis gas chromatography – mass spectrometry (PyGC-MS) have been reported for determining the chemical compositions of polymers in forensic samples. Double-shot pyrolysis gas chromatography – mass spectrometry (DS-PyGC-MS) is an extension of single-shot pyrolysis gas chromatography – mass spectrometry (SS-PyGC-MS) which is the current PyGC-MS method used in most forensic laboratories. DS-PyGC-MS involves a preliminary thermal desorption GC-MS step, followed by the pyrolysis GC-MS step, with this second step being analogous to SS-PyGC-MS. The pyrolyser furnace operates at a lower temperature during the thermal desorption step, allowing low volatility compounds, such as additives, to be thermally desorbed and detected, minimising interference from the polymeric component of the sample. This pilot study analysed four different polymeric substrates, commonly encountered in forensic casework, by DS-PyGC-MS. The substrates chosen were tyre rubber, road cones, cling film, and shotgun wads. The aim was to investigate whether more chemical information was generated by DS-PyGC-MS compared to SS-PyGC-MS, potentially providing increased discrimination of such samples. Qualitative results showed that tyre rubber and road cones were ideal substrates for DS-PyGC-MS. A wide range of additives were detected in these samples in the thermal desorption step, which were not detected using SS-PyGC-MS. All of the rubber tyres (n=5) and road cones (n=6) were able to be uniquely distinguished using DS-PyGC-MS. Some additional compounds were detected in the thermal desorption analysis of shotgun wads (n=4), providing increased discrimination compared to SS-PyGC-MS. For the cling film samples analysed (n=7) the polyethylene-based cling films (n=6) could not be distinguished from each other, with no compounds detected in the thermal desorption step. The other cling film sample contained a mixture of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) and could easily be distinguished from the polyethylene-based cling films using either SS- or DS-PyGC-MS, or other common analytical methods such as Fourier transform infrared spectroscopy (FTIR). This pilot study has demonstrated that DS-PyGC-MS has the potential to provide more comprehensive chemical composition information for some polymeric substrates and is a promising method for the forensic comparison of polymer evidence.

Electronic structure and thermoelectric properties of epitaxial Sc1−xVxNy thin films grown on MgO(001)

The electronic structure of Sc1−xVxNy epitaxial films with different alloying concentrations of V are investigated with respect to effects on thermoelectric properties. Band structure calculations on Sc0.75V0.25N indicate that V 3d states lie in the band gap of the parent ScN compound in the vicinity of the Fermi level. Thus, theoretically, the presence of light (dispersive) bands at the Γ point with band multiplicity is expected to lead to lower electrical resistivity, while flat (heavy) bands at X−W−K symmetry points are associated with higher Seebeck coefficients than that of ScN. Hence, to probe the thermoelectric properties experimentally, epitaxial Sc1−xVxNy thin film samples were deposited on MgO(001) substrates. All the samples showed N substoichiometry and pseudocubic crystal structure. The N-vacancy-induced states were visible in the Sc 2p x-ray absorption spectroscopy spectra. The reference ScN and Sc1−xVxNy samples up to x=0.12 were n type, exhibiting carrier concentration of 1021 cm−3, typical for degenerate semiconductors. For the highest V alloying of x=0.15, holes became the majority charge carriers, as indicated by the positive Seebeck coefficient. The underlying electronic structure and bonding mechanisms in Sc1−xVxNy influence the electrical resistivity, Seebeck coefficient, and Hall effect. Thus, this paper contributes to the fundamental understanding to correlate defects and thermoelectric properties to the electronic structure in the Sc-N system with V alloying. Published by the American Physical Society 2024

Preparation and characterization of chitosan-rice starch films incorporating Amomum verum Blackw essential oil for grape preservation

The preservation of perishable food items presents a significant challenge in the food industry. In this study, we investigated the development and characterization of chitosan-starch films incorporated with A. verum essential oil for application in grape preservation. The films were prepared using a solvent casting method, and their physical and antibacterial properties were thoroughly evaluated. The films demonstrated tensile strength values ranging from 21.28 MPa to 27.64 MPa and elongation at break between 71.24% and 84.23%. The water vapor permeability values for chitosan-starch films were from 2.04 kg/Pa·s·m to 2.51 kg/Pa·s·m. In addition, the antibacterial activity of the films was assessed against Escherichia coli and Staphylococcus aureus. The results revealed notable inhibitory effects, with inhibition zones ranging from 14.41 mm to 21.00 mm. The films' efficacy in grape preservation was evaluated through storage experiments at room temperature for 9 days, comparing them with polypropylene film and unwrapped samples. The chitosan-starch films, particularly those containing 1.0% A. verum essential oil, exhibited superior performance in reducing weight loss and maintaining grape firmness compared to common packaging materials. Moreover, grapes covered with these current active bio-based films demonstrated higher antioxidant activity, indicating potential benefits for extending shelf life and preserving fruit quality. Chitosan-starch films incorporated with A. verum essential oil hold promise as effective and environmentally friendly packaging materials for grape preservation.

Application of interlayer perforation and installation of transparent elements in the technology of duplicated decorative polymer films

Objectives. To develop technologies for producing multilayer films of transparent thermoplastic polymers; to study methods of modifying their supramolecular structure; and to determine their optical properties by means of optical-polarization methods for the use of modified films as decorative and design materials in modern architecture.Methods. Industrial samples of polystyrene, low-density polyethylene, polypropylene, and polyvinyl chloride films from various manufacturers (Don Polimer, Vektor, and Sibur) were the objects of the study. The optical properties of the films were studied by means polarized-light spectrophotometry. In order to modify the supramolecular structure of the polymers, the surfaces of the films were treated under isometric conditions with volatile solvents or their aqueous solutions. Parts of the layers of multilayer films were removed by cutting with a punching knife using a press or with a manual device for perforating printing materials.Results. The spectral characteristics of multilayer films of several transparent thermoplastic polymers in polarized light were determined. The study showed that a wide palette of colors and contrasting images can be obtained by mechanically removing part of the layers of multilayer films. The phenomenon of pseudo-disappearance of the outermost layer was discovered after treatment of a stack of films under isometric conditions with volatile solvents or their aqueous solutions.Conclusions. Based on the example of large-scale production thermoplastics, it was shown that a combination of technological methods of stacking, perforation, and local plasticization of films of transparent thermoplastic polymers can produce pleochroic multicolor materials for a range of human activities. The possibility of hidden coding of information on multilayer packaging materials, and its visualization and instrumental reading in polarized light was confirmed by color differential and contrast of 150 and 60 units, respectively. It was also shown that several monochrome tones of different lightness and brightness can be obtained by varying the number of layers or perforating the films in multilayer materials.

Centimeter-scale above room temperature ferromagnetic Fe3GaTe2 thin films by molecular beam epitaxy

Abstract Fe3GaTe2, as a layered ferromagnetic material, has a Curie temperature (T c ) higher than room temperature, making it the key material in the next generation of spintronic devices. To be used in practical devices, large-size and high-quality Fe3GaTe2 thin films need to be prepared. Here, the centimeter-scale thin film samples with high crystal quality and above room temperature ferromagnetism with strong perpendicular magnetic anisotropy (PMA) have been prepared by molecular beam epitaxy technology. Furthermore, the T c of the samples raises as the film thickness increases, and reaches 367 K when the film thickness is 60 nm. This study provides material foundations for the new generation of van der Waals spintronic devices and paves the way for the commercial application of Fe3GaTe2.

The Impact of Water on Polylactide – Polybutylene Adipinate Terephthalate Blends

Mixing in the melt followed by pressing, blends of polylactide — polybutylene adipate terephthalate of various compositions were obtained. The content of polybutylene adipate terephthalate in blends was 10, 20 and 30 wt. %. The effect of water on film samples at a temperature of 22 ± 2°C for 270 days was studied. After exposure to water, a change in morphology was detected: turbidity of the samples and the appearance of defects. The thermophysical characteristics before and after hydrolytic degradation were determined by differential scanning calorimetry. A decrease in the cold crystallization temperature in pure polylactide and with a low content of polybutylene adipate terephthalate, and the disappearance of the cold crystallization peak at a content of 20 and 30 wt. % of polybutylene adipate terephthalate were shown. The degree of crystallinity of polylactide after exposure to water tended to increase. Changes in the chemical structure of mixed samples were monitored by IR spectroscopy.

Crystallographic orientation dependence in creep deformation of micron-thick silicon films for 3-D microstructures

In this study, the steady-state creep deformation properties of 5 μm-thick single crystal silicon (Si) films at elevated temperatures were investigated using punch creep-forming tests for the design of three-dimensional (3-D) microstructured MEMS. The relationship between the creep strain rate and stress of the Si films with {100}, {110}, and {111} planes at temperatures of 1223–1323 K was derived using finite element analysis following punch creep-forming tests, and a power-law creep constitutive equation for Si films was determined. The steady-state creep properties of the Si film samples varied clearly with crystallographic orientations. Among the three crystallographic orientations, the creep strain rate of the micron-thick Si films was the fastest for the {011} plane, followed by the {111} and {001} planes, in the applied stress range of 110 MPa to 220 MPa. This is consistent with the increasing order of magnitude of the thermal activation energy. The crystallographic orientation dependence of the steady-state creep properties of Si films is discussed based on the mobility of dislocation gliding per unit lattice and scanning electron microscope observations. The sample-size dependence of the creep strain rate of Si with the {001} plane was clearly observed between the micron- and millimeter-thick samples, which was attributed to the difference in the frequency factor of the power-law creep. However, the thermal-activation energy remained constant. This study successfully revealed the steady-state creep properties of Si films and provided useful engineering data for the design of 3-D Si-MEMS fabrication by the plastic processing of Si films.

Development of a blue innovative antioxidant, biodegradable packaging material with Clitoria ternatea L. flos

Today, the packaging industry, and in particular the plastic packaging industry, are going to experience a number of challenges as a result of the provisions included in the directive on reducing the environmental impact of plastic packaging materials. Therefore, much attention is being paid to bio-based packaging based on natural and biodegradable polymers. Focus is being placed on natural additives with antioxidant properties to materials, eliminating the risks associated with the migration of chemical, often harmful substances into food. Therefore, in the present study, we obtained a blue antioxidant and biodegradable packaging material with flowers of Clitoria ternatea L., which is additionally safe against selected plants and invertebrates. Furthermore, we observed that the addition of blue matcha improved the barrier properties of the tested films. Samples with matcha CM (cellulose/matcha) and CZM (cellulose/gelatin/matcha) showed WVTR values of 14.44 [g/m2ˑd] and 9.34 [g/m2ˑd], respectively. Antioxidant activity testing by both the DPPH radical and FRAP methods showed the activity of the film containing the matcha extract. The extract alone had the highest activity (DPPH IC50 = 1.44 mg/ml; FRAP IT0.5 = 0.64 mg/ml). CM film had stronger antioxidant activity than CZM film. The film samples without matcha were characterised by TS values of 13.54 [MPa] and 22.24 [MPa], respectively. In contrast, their elongation at break was 74.87 [%] and 41.04 [%]. The samples containing matcha additives showed the weakest mechanical properties: CM and CZM. The cellulose/matcha film (CM) had TS and EAB values of 5.11 [MPa] and 5.05 [%], respectively. Whereas the cellulose/gelatin/matcha film (CZM) had TS and EAB values of 6.45 [MPa] and 1.54 [%], respectively. Application of a high concentration of matcha resulted in a separation of the phase leading to a weakening of the mechanical properties of the films. The observed change in the optical performance of matcha-containing films in this study was due to the blue colour of matcha, which is an effect of the presence of dried flowers. Furthermore, the blue colour of the packaging material has a marketing role as it can make the packaging product ‘stand out’ on the shop shelf.

Recovery and characterization of cellulose microfibers from fallen leaves and evaluation of their potential as reinforcement agents for production of new biodegradable packaging materials.

In the present work, cellulose microfibers (CMFs) isolated from fallen autumn leaves of cherry plum (Prunus cerasifera pissardii nigra), white mulberry (Morus alba) and plane (Platanus orientalis) trees were characterized and used as reinforcement agents in sodium alginate-based biodegradable films. Fourier transform infrared spectroscopy (FT-IR) characterization showed that the CMFs were successfully isolated from the leaves with high purity. The extracted CMFs had a particle size ranging from 321.20 nm to 632.26 nm and negative zeta potential values (-27.33 to -21.40). The extraction yield of CMFs ranged from 19.53% to 26.00%. Incorporation of the leaf-derived CMFs into sodium alginate based films (1%, w:w) increased their tensile strength (from 153.73 to 187.78 MPa) and elongation at break values (from 105.97% to 89.90%) and significantly decreased oxygen (from 121.46 to 75.56 meq kg-1) and water vapor permeabilities (from 2.36 to 1.60 g mm h-1 m-2 kPa-1)(p < 0.05). Furthermore, the supplementation of CMFs into the biopolymer matrix had no significant effect on the color (L*: 85.35-85.67; a*: -0.75-0.71; b*: 4.23-4.94) and moisture content (44.64-48.42%) of the film samples, although the thickness increased (40.33-94.66 μm). Scanning electron microscopy (SEM) images showed that CMFs were homogeneously dispersed in the film matrix. Overall, this study confirms that fallen cherry plum, white mulberry, and plane leaves are valuable sources of CMFs which could be used in the manufacturing of biodegradable nanocomposite films as reinforcement agents.

Magnetic field-augmented photoelectrochemical water splitting in Co3O4 and NiO nanorod arrays

Effective charge separation is crucial for improving the sensitivity of photoelectrochemical studies. Here, we provide an immense magnetic field-based electron spin polarization approach for an efficient charge carrier separation. We have fabricated NiO and Co3O4 thin film and nanorod arrays by electron beam evaporation glancing angle method followed by annealing in a two-zone furnace. The photoelectrochemical performance was investigated for NiO and Co3O4 samples in the presence and absence of a magnetic field. The NiO and Co3O4 nanorods array samples exhibit better absorption compared with the thin film samples. The Co3O4 and NiO nanorod arrays showed the highest photocurrent density of 0.12 and 0.55 mA/cm2 in a magnetic field. The superior photoelectrochemical response of NiO and Co3O4 nanorods in a magnetic field could be ascribed to the limitation of non-radiative recombination of carriers manipulated by Lorentz force and spin polarization. Furthermore, the electrochemical impedance spectra of NiO and Co3O4 nanorod arrays in a magnetic field show the least charge transfer resistance. This study sheds light on the interaction process between external fields and radiative/non-radiative recombination of manipulating carriers. Thus, the application of a magnetic field presents an efficient and versatile approach to enhance the performance of photoelectrodes in solar water splitting.

Annealing effects on 100 keV silicon negative ions implanted SiO2 thin films

SiO2 thin film of thickness 300 nm grown on p-type silicon substrate was implanted with 100 keV silicon negative ions for the fluences of 1 × 1016, 5 × 1016, and 1 × 1017 ions cm−2. The implanted samples were investigated using an energy-dispersive X-ray (EDX) spectroscopic technique, and the samples were annealed at a temperature of 900 oC under N2 ambient. Ultraviolet–visible near infrared (UV-Vis-NIR) spectroscopy has been used to investigate the implanted SiO2 thin film samples before and after thermal annealing. EDX results revealed an increase in the atomic percentage and weight percentage of silicon ions as compared to oxygen ions in SiO2 thin film. This may be due to the increase in the concentration of silicon ions with the increase of implanted ion fluences within the SiO2 thin film. UV-Vis-NIR studies showed higher transmittance for thermally annealed samples as compared to non-annealed samples. This may be attributed to the creation of a new SiOx phase in the SiO2 matrix at higher temperatures. UV-Vis-NIR studies also exhibited an increase in the energy band gap value after thermal annealing. This effect may be related to the formation of silicon nanoclusters in SiO2 thin film.

Optimization of Thermoelectric Properties and Physical Mechanisms of Cu2Se-Based Thin Films via Heat Treatment.

Cu2Se is an attractive thermoelectric material due to its layered structure, low cost, environmental compatibility, and non-toxicity. These traits make it a promising replacement for conventional thermoelectric materials in large-scale applications. This study focuses on preparing Cu2Se flexible thin films through in situ magnetron sputtering technology while carefully optimizing key preparation parameters, and explores the physical mechanism of thermoelectric property enhancement, especially the power factor. The films are deposited onto flexible polyimide substrates. Experimental findings demonstrate that films grown at a base temperature of 200 °C exhibit favorable performance. Furthermore, annealing heat treatment effectively regulates the Cu element content in the film samples, which reduces carrier concentration and enhances the Seebeck coefficient, ultimately improving the power factor of the materials. Compared to the unannealed samples, the sample annealed at 300 °C exhibited a significant increase in room temperature Seebeck coefficient, rising from 9.13 μVK-1 to 26.73 μVK-1. Concurrently, the power factor improved from 0.33 μWcm-1K-2 to 1.43 μWcm-1K-2.

Cobalt-doped ZnO nanoparticles and PLD-deposited thin film forms: structure, optical properties and nature of magnetic anisotropy.

Cobalt-doped zinc oxide nanoparticles (NPs) were synthesized using a modified sol-gel method. Thereafter, the obtained powder was deposited on a Suprasil glass substrate by employing a pulsed laser deposition (PLD) technique. X-ray diffraction analysis with Rietveld refinement confirmed a hexagonal wurtzite ZnO phase belonging to the P63 mc space group for both samples in the NP and thin film forms. In particular, the thin film exhibited an intensive (002) XRD peak, indicating that it had a preferred c-axis orientation owing to the self-texturing mechanism. No segregated secondary phases were detected. The crystallite structure, morphology, and size were investigated using high-resolution transmission electron microscopy (HRTEM). To study the crystalline quality, structural disorder, and defects in the host lattice, we employed Raman spectroscopy. UV-vis-NIR spectroscopy was performed to confirm the nature of the Co-doped ZnO NP powder and the film. The chemical states of oxygen and zinc in the thin film sample were also investigated via X-ray photoelectron spectroscopy (XPS). The M-T curve could be successfully fitted using both the three-dimensional (3D) spin-wave model and Curie-Weiss law, confirming the mixed state existence of weak ferromagnetic (FM) and paramagnetic (PM) phases. Magnetic interaction was quantitatively studied and explained by polaronic percolation of bound magnetic polarons (BMPs). Analysis of magnetic symmetry of the topological antiferromagnetic as-deposited thin film using torque measurements was performed. Based on a phenomenological model, it was revealed that the structure gives rise to uniaxial magneto-crystalline anisotropy (UMA) with the magnetic easy axis parallel to the c-axis.

Layer-by-layer assembly of a [Fe-(pyrazine){Pd(CN)4}] spin crossover thin film.

[Fe-(pyrazine){Pd(CN)4}] (pyrazine = pz) thin films were fabricated using a layer-by-layer assembly approach, a method known to be tunable, versatile, and scalable, since thin films are better-suited for industrial applications. In this study, [Fe-(pz){Pd(CN)4}] powder was synthesized, and the results obtained from a vibrating sample magnetometer verified the presence of an abrupt hysteresis loop with widths of 45 K centered around 300 K, indicating good cooperativity. Super conducting quantum interference device magnetometry results indicated a slow spin transition with temperature but with evidence of hysteresis for thin film samples. X-ray absorption analysis provided further support of the spin crossover behavior but differs from the magnetometry because the spin state transition at the surface differs from the bulk of the thin film. X-ray photoelectron spectroscopy provided some insight into issues with the film deposition process and multiplex fitting was used to further support the claim that the surface of the film is different than the bulk of the film.