Electron Microscopy Mapping Research Articles

Combining Electron Microscopy and Elemental Mapping for the Investigation of Zeolite Crystallization

Combining Electron Microscopy and Elemental Mapping for the Investigation of Zeolite Crystallization

Core–shell upconversion nanoparticles with suitable surface modification to overcome endothelial barrier

Upconversion nanoparticles (UCNPs), capable of converting near-infrared (NIR) light into high-energy emission, hold significant promise for bioimaging applications. However, the presence of tissue barriers poses a challenge to the effective delivery of nanoparticles (NPs) to target organs. In this study, we demonstrate the core–shell UCNPs modified with cationic biopolymer, i.e., N, N-trimethyl chitosan (TMC), can overcome endothelial barriers. The core–shell UCNP is composed of NaGdF4: Yb3+,Tm3+ (16.7 ± 2.7 nm) as core materials and silica (SiO2) shell. The average particle size of UCNPs@SiO2 is estimated at 26.1 ± 3.7 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM) and element mapping shows the formation of hexagonal crystal structure of β-NaGdF4 and elements doping. The surface of UCNPs@SiO2 has been modified with poly(ethylene glycol) (PEG) to enhance water dispersibility and colloidal stability, and further modified with TMC with the zeta potential increasing from -2.1 ± 0.96 mV to 26.9 ± 12.6 mV. No significant toxic effect is imposed to HUVECs when the cells are treated with core–shell UCNPs with surface modification up to 250 µg/mL. The transport ability of the core–shell UCNPs has been evaluated by using the in vitro endothelial barrier model. Transepithelial electrical resistance (TEER) and immunofluorescence staining of tight junction proteins have been employed to verify the integrity of the in vitro endothelial barrier model. The results indicate that the transport percentage of the UCNPs@SiO2 with PEG and TMC through the model is up to 4.56%, which is twice higher than that of the UCNPs@SiO2 with PEG but without TMC and six times that of the UCNPs@SiO2.

Ligand Identification in CryoEM and X-ray Maps Using Deep Learning.

Accurately identifying ligands plays a crucial role in the process of structure-guided drug design. Based on density maps from X-ray diffraction or cryogenic-sample electron microscopy (cryoEM), scientists verify whether small-molecule ligands bind to active sites of interest. However, the interpretation of density maps is challenging, and cognitive bias can sometimes mislead investigators into modeling fictitious compounds. Ligand identification can be aided by automatic methods, but existing approaches are available only for X-ray diffraction and are based on iterative fitting or feature-engineered machine learning rather than end-to-end deep learning. Here, we propose to identify ligands using a deep learning approach that treats density maps as 3D point clouds. We show that the proposed model is on par with existing machine learning methods for X-ray crystallography while also being applicable to cryoEM density maps. Our study demonstrates that electron density map fragments can aid the training of models that can later be applied to cryoEM structures but also highlights challenges associated with the standardization of electron microscopy maps and the quality assessment of cryoEM ligands.

One Pot Green Synthesis of Zr doped NiO Nanoparticles using Annona squamosa Seed Extract: Characterization and Biological Properties

Pure and Zr-doped NiO nanoparticles were successfully synthesized through green synthesis using extract of Annona squamosa seeds. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy, field emission scanning electron microscopy (FESEM), EDAX (energy dispersive X-ray analysis) and elemental mapping analysis. The addition of zirconium dopant has been integrated into the single-phase NiO lattice structure as indicated by characterization findings. Furthermore, the antibacterial, antifungal and antioxidant properties of Zr-doped and undoped NiO NPs were thoroughly examined. As a result of the strong Zr-doped NiO NPs synergistic effect, the results showed that the Zr-doped NiO NPs have improved the biomedical properties when compared to the undoped NiO NPs. The optimized size and shape of the nanoparticles contributed significantly to their improved effectiveness against the microorganisms and oxidative stress.

Structural insights into calcium-induced conformational changes in human gelsolin

Gelsolin is known as one of the actin-binding proteins capable of severing and capping filamentous actin, and of undergoing structural changes in the presence of calcium ions to interact with actin filaments. In this study, single-particle 3D reconstruction using electron microscopy (EM) revealed that, in the presence of calcium, the structure of gelsolin undergoes structural changes before interacting with actin. These differences are subtle with similarities, as confirmed by the EM map. According to the results of the molecular dynamics simulations, these nuanced structural differences primarily manifest at the domain level when calcium is present. These results provide structural evidence that, in the presence of calcium, gelsolin enters a phase of conformational preparation to transition into the active state. This process enables gelsolin to bind to actin, whereupon gelsolin undergoes more drastic structural changes upon interaction with actin filaments, which allows it to participate in binding and severing to regulate the cytoskeleton. This is the first visualization of full-length gelsolin, and helps to clarify crucial aspects of the as of yet incompletely understood interaction between gelsolin and actin.

Concentration-Dependent Effects of MXene Nanocomposite-Loaded Carboxymethyl Cellulose on Wound Healing.

Nanoparticles (NPs) have emerged as a promising solution for many biomedical applications. Although not all particles have antimicrobial or regenerative properties, certain NPs show promise in enhancing wound healing by promoting tissue regeneration, reducing inflammation, and preventing infection. Integrating various NPs can further enhance these effects. Herein, the zinc oxide (ZnO)-MXene-Ag nanocomposite was prepared, and the conjugation of its three components was confirmed through scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) mapping analysis. In vitro analysis using the agar well diffusion technique demonstrated that ZnO-MXene-Ag nanocomposite exhibited high antimicrobial efficacy, significantly inhibiting Escherichia coli, Salmonella, and Candida albicans, and showing enhanced potency when combined with tetracycline, resulting in a 2.6-fold increase against Staphylococcus and a 2.4-fold increase against Pseudomonas. The efficacy of nanocomposite-loaded carboxymethyl cellulose (CMC) gel on wound healing was investigated using varying concentrations (0, 1, 5, and 10mg/mL). Wound healing was monitored over 21 days, with results indicating that wounds treated with 1mg/mL ZnO-MXene-Ag gel exhibited superior healing compared to the control group (0mg/mL), with significant improvements noted from Day 3 onward. Conversely, higher concentrations (10mg/mL) resulted in reduced healing efficiency, particularly notable on Day 15. In conclusion, the ZnO-MXene-Ag nanocomposite-loaded CMC gel is a promising agent for enhanced wound healing and antimicrobial applications. These findings highlight the importance of optimizing NP concentration to maximize therapeutic benefits while minimizing potential cytotoxicity.

The influence of the addition of titanium oxide nanotubes on the properties of 3D printed denture base materials.

In this study, the effects of adding titanium dioxide nanotubes (TiO2) to 3D-printed denture base resin on the mechanical and physical properties of denture bases were examined for the first time. The specimens were digitally created using 3D builder software from Microsoft Corporation through computer-aided design. In accordance with the test specifications for transverse strength, impact strength, hardness, surface roughness, and color stability, specimens were designed and printed with certain dimensions following relevant standards. TiO2 nanotubes (diameter: 15-30 nm and length: 2-3 μm) were added to the 3D-printed denture base resin (DentaBase, Asiga, Australia) at 1.0% and 1.5% by weight. Flexural strength, impact strength (Charpy impact), hardness, surface roughness, and color stability were evaluated, and the collected data were analyzed with ANOVA followed by Tukey's post hoc test (α = 0.05). Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDX) mapping were used to evaluate the dispersion of the nanotubes. Compared with those of the control group (0.0 wt.% TiO2 nanotubes), the average flexural, impact, and hardness values of the 1.0 and 1.5 wt.% TiO2 nanotube reinforcement groups increased significantly. Both nanocomposite groups showed significant color changes compared to that of the pure resin, and there was a considerable reduction in the surface roughness of the nanocomposites compared to that of the control group. Adding TiO2 nanotubes to 3D-printed denture base materials at 1.0 and 1.5 wt.% could enhance the mechanical and physical properties of the material, leading to better clinical performance. In terms of clinical applications, 3D-printed denture base material has been shown to be a viable substitute for traditional heat-cured materials. By combining this with nanotechnology, existing dentures could be significantly enhanced, promoting extended service life and patient satisfaction while addressing the shortcomings of the current standard materials.

Investigation of effective parameters on Fe/Ta thin films by plasma focus device: number of shots and distance from tip anode

This experimental investigation is the first to generate a surface iron-tantalum (Fe/Ta) alloy as a sublayer-layer using a plasma focus device. Examining how ion beams from a plasma focus device alloy iron and tantalum with varying melting points is one of the key objectives of this study. Fe/Ta thin film nanostructure and surface morphology were also examined. The distance from the tip anode and the varied number of shots are the experimental variables. Although tantalum's melting point (3020 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}) is generally known to be near to that of iron (2862 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ{\\rm C}$$\\end{document}), it is possible that iron vaporizes and partial alloying of iron with tantalum occurs before tantalum reaches its melting point. Fe/Ta thin film identification techniques include scanning electron microscopy, mapping of cross-section, energy dispersive X-ray spectroscopy, and X-ray diffraction pattern. Additionally, the composition of multilayer structures is examined using EDS. In conclusion, the results of the X-ray diffraction pattern showed that the number of shots had a significant impact on the residual strain degree of the thin films that were deposited. Furthermore, structures made of FeTa and Fe2Ta were produced. Additionally, photos from scanning electron microscopy and cross-section mapping verify that the sample with five shots at an 8 cm distance from the tip anode formed a uniform Fe/Ta alloy structure. The sample with five shots at a distance of 4 cm from the tip anode formed micro-island structures, as seen by scanning electron microscopy, with decreasing distance. Furthermore, depth elemental distribution revealed that the optimal depth of penetration in a homogenous material to develop alloying is best determined by number of PF shots.

Ultraviolet photon upconversion in Er–SiAlON under 1550 nm excitation

SiAlON ceramics are well known for their exceptional mechanical, thermal, and chemical stability, making them ideal for demanding industrial applications such as cutting tools, equipment for molten metal handling, extrusion molds, gas turbine engines, etc. Despite these applications, the potential for photonic applications such as photon upconversion (UC) in SiAlON ceramics remains less explored. This report demonstrates broad spectral photon UC properties in Er-doped SiAlON (Er–SiAlON) ceramics, covering the ultraviolet (UV) to near-infrared (NIR) range upon 1550 nm excitation. The Er–SiAlON ceramic was synthesized by hot press sintering. X-ray diffraction (XRD), transmission electron microscopy (TEM) and elemental mapping results confirmed the stabilization of the α-SiAlON phase by Er3+ ions. Optical spectra showed distinct transitions of Er³⁺ ions and high transparency of over 70 % in the mid-IR range for the sample thickness of 0.49 mm. Under 1550 nm excitation, UC emission spectra revealed UV, violet, blue, green, red, and NIR emissions. The Er³⁺ ions exhibited self-sensitization, acting both as sensitizers and activators for the UC luminescence. Decay curve analysis showed long excited state lifetimes, with ground state absorption (GSA), excited state absorption (ESA), and energy transfer UC (ETU) processes facilitating multi-photon absorption and diverse spectral emissions. Given the inherent mechanical properties of SiAlON ceramics, these findings highlight the potential of Er–SiAlON ceramics for advanced UC photonic devices operating in high-temperature and harsh environments.

Correlated 4D-STEM and EDS for the classification of fine Beta-precipitates in aluminum alloy AA 6063-T6

Tuning the properties of aluminum alloys AA 6063-T6 involves artificial aging to induce precipitate formation, particularly β’’ and β’ phases. Previous characterization challenges due to their similar appearance are addressed here by correlating 4D scanning transmission electron microscopy (4DSTEM) and energy-dispersive spectroscopy (EDS) mapping. This approach allows us to analyze the structure and composition of precipitates individually, overcoming limitations of conventional imaging and structural analysis techniques when the precipitates appear simultaneously, as is often the case. We present detailed characterizations of needle-shaped Beta precipitates, revealing distinct diffraction patterns (DPs) and compositional differences. The method's applicability extends beyond aluminum alloys, offering a promising strategy for complex composite material characterization with multimodal scanning transmission electron microscopy (STEM) techniques.

Wear mechanisms and material deposition of high-performance polymer composites for hydrogen compression

The transistion to renewable energy production is a main component in achieving the climate targets defined in the 2015 Paris Agreement. Power-to-gas concepts, where electrical energy is stored as hydrogen gas, require the design and operation of state-of-the-art reciprocating compressor technology to realize high pressure ratios and high volumetric flow rates for gas supply demands. The main challenges in designing machines suited for these operating conditions are high thermo-mechanical stresses acting on the piston sealing rings. High shear loads and minimal ring gap sizes demand material pairings with excellent wear resistance and sliding properties. This work investigates the life cycle limiting wear mechanisms present in the piston compressor and develops advanced concepts for piston rings in cylinder tribo-contacts. PI and PPS polymers reinforced with carbon fiber were modified with dry lubricating PTFE to fulfil the requirements of this highly stressed tribo-system. Tribo-tests were performed against steel countersurfaces with a linear oscillating tribometer in pin-on-plate configuration. The failure mechanisms were analysed utilizing scanning electron microscopy on cross-sections cut into the depth of the countersurface material with focused ion beam milling. 2D scanning transmission electron microscopy mapping supported by energy dispersive X-ray spectroscopy were performed to analyze the depth profile of the deposited tribo-layer elements on the wear track.

Development of Chitosan/Mg−Zn−HAP/ZrO2 Bilayer Coating on Ti Alloy for Biomedical Applications

AbstractTitanium alloys (Ti−6Al−4V) are being used in many biomedical applications due to their unique properties of bioactivity, excellent mechanical properties, low toxicity, biocompatibility, and long‐term implant application for their satisfactory corrosion resistance. We have developed a new two‐step fabrication process of zirconium oxide (ZrO2) and Chitosan/Mg−Zn−HAP (Chitosan/M−HAP) bilayer layer coating on Ti alloy for biomedical applications. Flower‐structured bilayers were coated by the electrochemical deposition method. Electrochemically deposited bilayer‐coated Ti alloy specimens were characterized by various analytical techniques like field‐emission scanning electron microscope (FE‐SEM), X‐ray diffraction (XRD), and EDS mapping analysis. Furthermore, the developed bilayer (Chitosan/Mg−Zn−HAP/ZrO2) coated Ti alloy samples improved mechanical properties such as adhesion strength (20.1±0.4 MPa) and hardness (446±4 Hv), compared to other coatings. An investigation of polarization curves showed a positive shift in the polarization values (Ecorr, and Icorr) of the Chitosan/M−HAP/ZrO2 bilayer coatings on Ti alloy. Bilayer‐modified Ti alloy samples show good antimicrobial response toward Gram‐negative and Gram‐positive bacteria. Meanwhile, the cell viability and proliferation of the bilayer‐coated samples were evaluated and the exhibited result improved cell proliferation, and bioactivity compared to other coated materials. From the results, it can be evident that the developed Chitosan/Mg−Zn−HAP/ZrO2 bilayer‐coated Ti alloy could be a good potential candidate for biomedical applications.

Characterization of a thermally stable red-light-emitting phosphor: synthesis, photoluminescence, and thermoluminescence studies of CsCaF3 compound doped with Eu3+ for solid-state lighting applications

In this investigation, we focused on the synthesis and characterization of CsCaF3 compound doped with europium (Eu3+) ions using a solid-state route. To analyze the crystal structure of the synthesized phosphors, X-ray diffraction analysis was employed. Additionally, the doped sample underwent examination of surface morphology and elemental composition through Field Emission Scanning Electron Microscopy and EDAX mapping. The color of the pure and doped CsCaF3 sample was quantified and fitted using Color coordinate graph by the Commission Internationale de l'Eclairage (CIE). The red emission on the doped CsCaF3 compound was detected at 465 nm, which is the transition from 5D0 to 7Fj (j = 0, 1, 2, and 3). The 0.5 mol. % Eu3+ doped CsCaF3 sample was found to have a color purity of 81% and an associated color temperature of 1660 K, indicating its suitability for aesthetic lighting applications. Furthermore, thermoluminescence study, electron paramagnetic resonance (EPR), and effective atomic number (Z eff) calculations were conducted to provide valuable information for potential radiation dosimetry applications.

Boosting carbon capture with CO2-Ultrapermeable molecularly imprinted membranes

Mixed matrix membrane (MMM) is one of the most promising candidates for exceeding the gas separation upper bound, while fillers can largely determine their ultimate performance. The molecular imprinting technique was first employed to prepare a layer containing rich CO2 adsorption sites on the UiO-66-NH2 surface for fabricating highly CO2-permeable PIM-1-based MMMs with higher selectivity. Transmission electron microscopy (TEM) and element mapping confirmed the successful formation of the core-shell structure for the imprinted metal-organic frameworks (MOFs). The MMMs prepared with imprinted MOFs present enhanced CO2 permeability and CO2/N2 selectivity, higher compatibility between polymers and fillers, and better mechanical strength compared to the MMMs with the pristine UiO-66-NH2. The MMMs formed with 5 wt% imprinted MOFs showed superior CO2/N2 separation performance beyond the 2019 upper bound with an ultrahigh CO2 permeability of 13,000 barrer (increased twice compared to pristine PIM-1 membrane). Moreover, with a filler content of 13 wt%, the obtained membrane maintains good mechanical properties, which indicates the benefit of the imprinted layer for the improvement of the filler loading inside a PIM-1 matrix. The membranes showed decreased CO2 permeability and CO2/N2 selectivity under the wet conditions, but stable performances over 46 hours of dynamic testing. The results indicate the presented approach for filler modification via molecular imprinting is a promising strategy for the enhancement of the MMM separation performance.

Synthesis of type-II SrTiO3/ZnO heterojunction material for photocatalytic degradation of methylene blue under sunlight

This work presents the synthesis of ZnO, SrTiO3, and SrTiO3/ZnO catalysts by simple hydrothermal method. The obtained materials were characterized by X-Ray Diffraction (XRD), Fourier transformation infrared spectra (FT-IR), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDS) and element mapping images, Photo-luminescence spectroscopy (PL), and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The photocatalytic activity of the synthesized materials was assessed by degradation of methylene blue (MB) under sunlight. In particular, SrTiO3/ZnO displayed outstanding photocatalytic activity compare to individual catalysts. Our findings have revealed an improvement of photogenerated charge separation and the dominating role of the holes and electrons in the degradation of MB.

Electron Microscopic Mapping of Mitochondrial Morphology in the Cochlear Nerve Fibers.

To enable nervous system function, neurons are powered in a use-dependent manner by mitochondria undergoing morphological-functional adaptation. In a well-studied model system-the mammalian cochlea, auditory nerve fibers (ANFs) display distinct electrophysiological properties, which is essential for collectively sampling acoustic information of a large dynamic range. How exactly the associated mitochondrial networks are deployed in functionally differentiated ANFs remains scarcely interrogated. Here, we leverage volume electron microscopy and machine-learning-assisted image analysis to phenotype mitochondrial morphology and distribution along ANFs of full-length in the mouse cochlea inner spiral bundle. This reveals greater variance in mitochondrial size with increased ANF habenula to terminal path length. Particularly, we analyzed the ANF terminal-residing mitochondria, which are critical for local calcium uptake during sustained afferent activities. Our results suggest that terminal-specific enrichment of mitochondria, in addition to terminal size and overall mitochondrial abundance of the ANF, correlates with heterogenous mitochondrial contents of the terminal.

Validation of electron-microscopy maps using solution small-angle X-ray scattering.

The determination of the atomic resolution structure of biomacromolecules isessential for understanding details of their function. Traditionally, such a structure determination has been performed with crystallographic or nuclear resonance methods, but during the last decade, cryogenic transmission electron microscopy (cryo-TEM) has become an equally important tool. As the blotting and flash-freezing of the samples can induce conformational changes, external validation tools are required to ensure that the vitrified samples are representative of the solution. Although many validation tools have already been developed, most of them rely on fully resolved atomic models, which prevents early screening of the cryo-TEM maps. Here, a novel and automated method forperforming such a validation utilizing small-angle X-ray scattering measurements, publicly available through the new software package AUSAXS, is introduced and implemented. The method has been tested on both simulated and experimental data, where it was shown to work remarkably well as a validation tool. The method provides a dummy atomic model derived from the EM map which best represents the solution structure.

Synergistic degradation of metronidazole and penicillin G in aqueous solutions using AgZnFe2O4@chitosan nano-photocatalyst under UV/persulfate activation

In recent years, the persistence of pharmaceutical contaminants like metronidazole (MNZ) and penicillin G (PG) in water bodies has become a major environmental concern. The present research studied the simultaneous degradation of MNZ and PG utilizing an AgZnFe2O4@Ch catalyst generated through the co-precipitation technique as an effective stimulator for persulfate (PS) in the existence of UV light. The structure of the AgZnFe2O4@Ch catalyst was characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, vibrating-sample magnetometer, and energy dispersive spectroscopy mapping. After 50 minutes of reaction time under the ideal operating conditions, which included 0.4 g/L of catalyst, 4 mM of PS, 5 mg/L of MNZ and PG, and a pH of 5, the highest MNZ and PG degradation of 81.5 % and 82.3 % were obtained. Statistical parameters, including the R2 values of 0.985 for MNZ and 0.981 for PG, indicate a very good agreement between the predicted and observed values. The Garson's method analysis revealed that PS dosage had the greatest impact on MNZ degradation, while the initial concentration of PG exerted the most significant influence on PG degradation. The Langmuir-Hinshelwood model has surface reaction rate constants (Kc) of 0.954 (mg/L.min) and adsorption equilibrium constants (KL-H) of 0.032 (L/mg) for both antibiotics, respectively. The claimed mechanism was illustrated by the free radical scavenging studies, which demonstrated that the SO•4- radicals were the main radicals involved in the degradation of MNZ and PG. A last investigation of the catalyst's regeneration revealed that it had satisfactory chemical stability after five cycles of usage and regeneration using chemical approaches.

Titania-Graphene Oxide Nanocomposite-Based Philadelphia-Positive Leukemia Therapy.

Philadelphia-positive (Ph+) leukemia is a type of blood cancer also known as acute lymphoblastic leukemia (ALL), affecting 20-30% of adults diagnosed worldwide and having an engraved prognosis as compared to other types of leukemia. The current treatment regimens mainly rely on tyrosine kinase inhibitors (TKIs) and bone marrow transplants. To date, several generations of TKIs have been developed due to associated resistance and frequent relapse, with cardiovascular system anomalies being the most devastating complication. Nanotechnology has the potential to address these limitations by the targeted drug delivery and controlled release of TKIs. This study focused on the titanium dioxide (TiO2) and graphene oxide (GO) nanocomposite employment to load nilotinib and ponatinib TKIs for therapy of Ph+ leukemia cell line (K562) and Ba/F3 cells engineered to express BCR-ABL oncogene. Meanwhile, after treatment, the oncogene expressing fibroblast cells (Rat-1 P185) were evaluated for their colony formation ability under 3D conditions. To validate the nanocomposite formation, the TiO2-GO nanocomposites were characterized by scanning electron microscope, DLS, XRD, FTIR, zeta potential, EDX, and element mapping. The TKI-loaded TiO2-GO was not inferior to the free drugs after evaluating their effects by a cell viability assay (XTT), apoptosis induction, and colony formation inhibition. The cell signaling pathways of the mammalian target of rapamycin (mTOR), signal transducers and activators of transcription 5 (STAT5), and extracellular signal-regulated kinase (Erk1/2) were also investigated by Western blot. These signaling pathways were significantly downregulated in the TKI-loaded TiO2-GO-treated groups. Based on the findings above, we can conclude that TiO2-GO exhibited excellent drug delivery potential that can be used for Ph+ leukemia therapy in the future, subject to further investigations.

Relevance of Platinum Underlayer Crystal Quality for the Microstructure and Magnetic Properties of the Heterostructures YbFeO3/Pt/YSZ(111).

The hexagonal ferrite h-YbFeO3 grown on YSZ(111) by pulsed laser deposition is foreseen as a promising single multiferroic candidate where ferroelectricity and antiferromagnetism coexist for future applications at low temperatures. We studied in detail the microstructure as well as the temperature dependence of the magnetic properties of the devices by comparing the heterostructures grown directly on YSZ(111) (i.e., YbPt_Th0nm) with h-YbFeO3 films deposited on substrates buffered with platinum Pt/YSZ(111) and in dependence on the Pt underlayer film thickness (i.e., YbPt_Th10nm, YbPt_Th40nm, YbPt_Th55nm, and YbPt_Th70nm). The goal was to deeply understand the importance of the crystal quality and morphology of the Pt underlayer for the h-YbFeO3 layer crystal quality, surface morphology, and the resulting physical properties. We demonstrate the relevance of homogeneity, continuity, and hillock formation of the Pt layer for the h-YbFeO3 microstructure in terms of crystal structure, mosaicity, grain boundaries, and defect distribution. The findings of transmission electron microscopy and X-ray diffraction reciprocal space mapping characterization enable us to conclude that an optimum film thickness for the Pt bottom electrode is ThPt = 70 nm, which improves the crystal quality of h-YbFeO3 films grown on Pt-buffered YSZ(111) in comparison with h-YbFeO3 films grown on YSZ(111) (i.e., YbPt_Th0nm). The latter shows a disturbance in the crystal structure, in the up-and-down atomic arrangement of the ferroelectric domains, as well as in the Yb-Fe exchange interactions. Therefore, an enhancement in the remanent and in the total magnetization was obtained at low temperatures below 50 K for h-YbFeO3 films deposited on Pt-buffered substrates Pt/YSZ(111) when the Pt underlayer reached ThPt = 70 nm.