Grazing Incidence X-ray Diffraction Studies Research Articles

Interactions of Brominated Flame Retardants with Membrane Models of Dehalogenating Bacteria: Langmuir Monolayer and Grazing Incidence X-ray Diffraction Studies.

Brominated flame retardants (BFRs) are small organic molecules containing several bromine substituents added to plastics to limit their flammability. BFRs can constitute up to 30% of the weight of some plastics, which is why they are produced in large quantities. Along with plastic waste and microplastic particles, BFRs end up in the soil and can easily leach causing contamination. As polyhalogenated molecules, multiple BFRs were classified as persistent organic pollutants (POPs), meaning that their biodegradation in the soils is especially challenging. However, some anaerobic bacteria as Dehaloccocoides can dehalogenate BFRs, which is important in the bioremediation of contaminated soils. BFRs are hydrophobic, can accumulate in plasma membranes, and disturb their function. On the other hand, limited membrane accumulation is necessary for BFR dehalogenation. To study the BFR-membrane interaction, we created membrane models of soil dehalogenating bacteria and tested their interactions with seven legacy and novel BFRs most common in soils. Phospholipid Langmuir monolayers with appropriate composition were used as membrane models. These membranes were doped in the selected BFRs, and the incorporation of BFR molecules into the phospholipid matrix and also the effects of BFR presence on membrane physical properties and morphology were studied. It turned out that the seven BFRs differed significantly in their membrane affinity. For some, the incorporation was very limited, and others incorporated effectively and could affect membrane properties, while one of the tested molecules induced the formation of bilayer domains in the membranes. Thus, Langmuir monolayers can be effectively used for pretesting BFR membrane activity.

Antiferromagnetically coupled CoFe/MgO/CoFe stacks

Exchange coupling (EC) in as-deposited and annealed Co80Fe20 (CoFe)/MgO/Co80Fe20 (CoFe) for MgO thickness spanning 0.45 to 4.5 nm has been studied. Unlike relevant existing results and theories, antiferromagnetic EC behaviors were observed in annealed CoFe/MgO/CoFe with 2.7-nm MgO insulating barrier. Interestingly, a transition from antiferromagnetic to nearly paramagnetic response to applied magnetic field was found around 520 °C corresponding to Néel temperature of CoFe2O4. Based on grazing incidence x-ray diffraction study, oxide phases of CoO, Co3O4, and CoFe2O4 starts to be built in the interface annealed at 150 °C and then those of CoO, Fe3O4, Fe2O3, and CoFe2O4 are mostly distributed over the interface annealed at 250 °C. This indicates CoO and CoFe2O4 formed at the Co-rich interface act as antiferromagnetic sources giving rise to the exchange-coupled antiferromagnetic/ferromagnetic (AFM/FM) interface and then AFM EC into the CoFe/MgO/CoFe.

Interface engineered nanostructured phase formation at Se/In sites by Ag ion irradiation and its structural, optical and morphological behavior

Thermally evaporated Se/In bilayer films were irradiated by 120 MeV Ag ion at different fluences. Energy-dispersive X-ray fluorescence (EDXRF) spectra of the films showed the 1:2 ratio concentration of In and Se. After six months of preserving the films under ambient condition, four phases: In2Se3, In4Se3, In and Se developed in the films as revealed by Grazing incidence X-ray diffraction (GIXRD) study. The In4Se3 and In were completely insensitive to the irradiation while the other two phases (In2Se3 and Se) were completely amorphized at high ion fluences. The Poission fitting of the fluence dependence area under X-ray diffraction (XRD) peaks showed the radius of amorphized latent tracks along the path of 120 MeV Ag ions in In2Se3 and Se as 8.4 nm and 9.5 nm respectively. The lattice fringe images of High-resolution transmission electron microscopy (HRTEM) showed the presence of the four phases as observed by GIXRD study. The UV-visible study revealed the band gap reduction at the low fluence region from pristine to 3 × 1011ions cm−2 and increased at high fluence from 1 × 1012 ions cm-2 to 1 × 1013 ions cm-2. This variation of band gap may be due to the formation of localized states and annealing effect due to ion irradiation. Field emission scanning electron microscopy (FESEM) images showed the nano needle shaped structure formation at 1 × 1012 ions cm−2 which increased with ion fluences. The appearance of needle shaped structures may be due to the In2Se3 phase. The I-V study showed the excellent current response in mA range which enables the films for various electrical applications. The surface wettability study showed the hydrophobicity nature of the films which enables it for application in different coating materials.

Role of nickel in structural and mechanical properties of nc-WNNi sputtered nanocomposite coatings

Nanocomposites coatings offers a wide range of possibilities to promote hardness, oxidation resistance, wear resistance, etc properties significant for protective coatings. Finding new nanostructured coating with high hardness and thermal stabilities are the prime requirement of modern industries. In view of above, the nc-WNNi nanocomposite coatings were deposited using reactively sputtered method on silicon (100) substrate by varying the power of Nickel (Ni). The coatings were characterized by using grazing incidence X-ray diffraction (GIXRD), Field emission scanning electron microscope (FESEM), energy dispersive x-ray analysis (EDX), thickness profiler, four probe resistivity measurement and nanoindentation tester. Through GIXRD studies the desired face centered cubic W2N phase was confirmed, with decreasing crystallite size on increasing Ni power (content). FESEM image revels/suggest that at low Ni content, the film structure stabilized into well separated grains with the presence of grain boundary and were of uneven shape throughout. On increasing Ni power, the agglomeration increase and no clear signature of grain boundaries were visible. The resistivity of the films was found to be decreasing with increasing Ni content at different temperatures. Improved mechanical properties were observed at low Ni power (content), which drastically decreases with increasing Ni power. The highest hardness (H), elastic modulus (Er), elastic recovery (We), and resistance to plastic deformation (H3/E2) were obtained 26.60 GPa, 276.82 GPa, 69.80 GPa, 245 MPa respectively for nc-WN10Ni film. The nc-WN10Ni film shows the highest mechanical properties as compared to others.

Grazing incidence X-Ray diffraction: identifying the dominant facet in copper foams that electrocatalyze the reduction of carbon dioxide to formate.

Copper foams have been shown to electrocatalyze the carbon dioxide reduction reaction (CO2RR) to formate (HCOO-) with significant faradaic efficiency (FE) at low overpotentials. Unlike the CO2RR electrocatalyzed at copper foils, the CO2RR electrocatalyzed at porous copper foams selects for HCOO- essentially to the exclusion of hydrocarbon products. Formate is an environmentally friendly organic acid with many applications such as food preservation, textile processing, de-icing, and fuel in fuel cells. Thus, HCOO- is an attractive product from the CO2RR if it is produced at an overpotential lower than that at other electrocatalysts. In this study, grazing incidence X-ray diffraction (GIXRD) was used to identify the dominant surface facet of porous copper foams that accounts for its selectivity for HCOO- during the CO2RR. Included are data from the CO2RR at different temperatures using copper foams as the electrocatalyst. Under optimal reaction conditions at 2 °C, the FE for converting CO2 to HCOO- at Cu foams approaches 50% while the FE for hydrogen gas (H2) falls below 40%, a significant departure from that obtained at polycrystalline Cu foils. Computational studies by others have proposed (200) and (111) facets of Cu foils thermodynamically favour methane and other hydrocarbons, CO, HCOO- from the CO2RR. Results from the GIXRD studies indicate Cu foams are dominated by the (111) facet, which accounts for the selectivity of Cu foams toward HCOO- regardless of temperature used for the CO2RR.

Influence of lipophilicity of anthracyclines on the interactions with cholesterol in the model cell membranes – Langmuir monolayer and SEIRAS studies

The interactions of anthracyclines with biological membranes strongly depend on the drug lipophilicity, which might also determine the specific affinity to cholesterol molecules. Therefore, in this work we show the studies concerning the effect of two selected anthracyclines, daunorubicin (DNR) and idarubicin (IDA) on simple models of healthy (DMPC:Chol 7:3) and cancer cells membranes with increased level of cholesterol (DMPC:Chol 3:7) as well as pure cholesterol monolayers prepared at the air-water interface and supported on gold surface. It has been shown that more lipophilic IDA is able to penetrate cholesterol monolayers more effectively than DNR due to the formation of IDA-cholesterol arrangements at the interface, as proved by the thermodynamic analysis of compression-expansion cycles. The increased interactions of IDA were also confirmed by the time measurements of pre-compressed monolayers exposed to drug solutions as well as grazing incidence X-ray diffraction studies demonstrating differences in the 2D organization of cholesterol monolayers. Langmuir studies of mixed DMPC:Chol membranes revealed the reorganization of molecules in the cancer cell models at the air-water interface at higher surface pressures due to the removal of DNR, while increased affinity of IDA towards cholesterol allowed this drug to penetrate the layer more efficiently without its removal. The SEIRAS spectra obtained for supported DMPC:Chol bilayers proved that IDA locates both in the ester group and in the acyl chain region of the bilayer, while DNR does not penetrate the membranes as deeply as IDA. The increased penetration of the mixed phospholipid layers by idarubicin might be attributed to the higher lipophilicity caused by the lack of methoxy group and resulting in a specific affinity towards cholesterol.

Characterization of stabilized ZrO2 thin films obtained by sol-gel method

In this work, the characterization of ZrO2 thin films synthesized by the sol-gel method, using two different routes, is presented. Thin films were deposited by dip-coating on glass and Zircaloy-4 (Zry-4) substrates, and heat treated at 500 °C under atmospheric air. Characterization was carried out using X-Ray Diffraction (XRD), Grazing Incidence X-Ray Diffraction (GIXRD), High Temperature X-Ray Diffraction (HT-XRD), Raman Spectroscopy (RS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Electrical properties of films were studied by conductivity measurements. These films present a thickness of 90 and 200 nm on glass, depending on the synthesis route, and consist of nanocrystals with predominantly tetragonal phase. On coated Zry-4, a non-uniform but dense ZrO2 layer without cracks grows, in contrast with the un-coated Zry-4, where a thicker layer was formed with the presence of micro-fissures. A GIXRD study showed that both tetragonal and monoclinic phases are present in the oxide layer. Conductivity measurements indicated that these films have excellent insulating properties, with resistivity values that exceed 0.5 M Ω.cm below 300 °C. These exceptional properties and the retention of high symmetry phases make this method very attractive for growing good electrical insulator and anti-corrosion ZrO2 thin film coatings.

Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique.

A thin film of unsubstituted polythiophene (PT), an insoluble conjugated polymer, with molecular chains uniaxially oriented in plane was prepared by the friction transfer method. The structure of highly oriented thin films of PT was investigated using grazing-incidence X-ray diffraction (GIXD), ultraviolet–visible (UV–vis) spectroscopy, and infrared (IR) spectroscopy. The polarized UV–vis and IR spectra and GIXD measurements showed the PT molecular chains were well aligned in parallel to the friction direction. The GIXD studies clarified that the polymer backbones were aligned with very narrow distribution, such that the half-width was about 4 degrees. The degree of orientation of the PT friction-transferred film was higher compared with those of regioregular poly(3-alkylthiophene)s. Moreover, the GIXD results show a preferred orientation where the a-axis is perpendicular to the substrate plane.

The effect of the polyethylene glycol chain length of a lipopolymer (DSPE-PEGn) on the properties of DPPC monolayers and bilayers

Due to the growing importance of controlled drug delivery systems (DDS), the main task of nanotechnology is to develop stable, effective and non-toxic nanocarriers in which the drug can be encapsulated and delivered to a specific diseased site in the patient's body. Currently, one of the most popular ways to improve the pharmacokinetic and physicochemical properties of liposomes is introducing into their structure poly(ethylene glycol) chains conjugated with 1,2-disteroil-sn-glycero-3-phosphoethanolamine (DSPE) molecules. Because the research so far does not give an unequivocal answer which length of PEG chains is more beneficial for liposomes properties, the aim of this work was to investigate the influence of this parameter (DSPE-PEG350, DSPE-PEG750 and DSPE-PEG2000) on model DPPC membrane. The studies were performed on monolayer and bilayer systems and were related to the surface pressure measurements, Brewster angle microscopy experiments, Grazing Incidence X-ray Diffraction studies, dynamic light scattering and zeta potential measurements and the experiments with the calcein release and steady-state fluorescence anisotropy of DPH. The obtained results proved that the molecular organization of the DPPC membrane strongly depends on the length of poly(ethylene glycol) chains conjugated with DSPE. Moreover, the addition of different lengths of polymer chains changes the properties of formulated liposomes, especially their stability, permeability, size and surface charge.

Annealing temperature-driven near-surface crystallization with improved luminescence in self‐patterned alumina films

The impact of annealing on luminescence properties of radio-frequency magnetron sputtering grown alumina films and their possible application in radiation measurement are presented. Here, grazing incidence X-ray diffraction study reveals the growth of amorphous alumina films, while the annealing treatment results in the gradual formation of nanocrystallites. They are found to be embedded in the amorphous matrix by cross-sectional Transmission Electron Microscopy for 1200 °C annealed thin film. The evolution of self-patterned wrinkles has also been observed at the surface by Scanning Electron Microscopy. A comprehensive analysis of optically active defect centers is carried out by room temperature photoluminescence (PL) measurement. This indicates a monotonic increase of oxygen vacancies (F centers) with increasing annealing temperature up to 1200 °C, though they are not directly correlated with the thermoluminescence (TL) results after exposing them to gamma radiation from a 60Co source. Based on PL analysis, the TL glow curves with increasing annealing temperature are elucidated in the light of the involvement of both trap centers and F-type recombination centers residing at grain boundaries. In terms of TL results, 1200 °C annealed alumina film is found to be superior to both the as-grown film, and the one annealed at 1100 °C. Finally, the linear TL response curves in the 1200 °C annealed film after exposing to both gamma radiation (up to 5 kGy) and energetic charged particles (80 MeV carbon ions) are demonstrated up to 130 kGy.

Understanding thickness dependent magnetic properties of Tb-Fe thin films

In this paper, we have attempted to understand the magnetic behaviour of Tb-Fe thin films grown with different thicknesses through detailed electron microscopy, magnetization measurements and magnetic domain imaging studies. Tb-Fe thin films over a range of thicknesses such as 50, 100, 200, 400, 600 and 800 nm were deposited on Si substrates using electron beam evaporation technique. Grazing incidence X-ray diffraction studies revealed that all the films were amorphous in nature. Microstructural studies using transmission electron microscopy showed columnar channel of voids extending from substrate to film surface. Magnetization measurements along the in-plane and out-of-plane direction indicated presence of out-of-plane magnetic anisotropy in all the films. Saturation magnetization and coercivity measured along the out-of-plane direction were found to vary with the thickness of the films. A very high coercivity of ~2000 mT was obtained for the film having thickness of 400 nm. Magnetic anisotropy calculations indicated a strong perpendicular magnetic anisotropy for the 400 nm thick film. The variation of magnetic anisotropy with film thickness was correlated with the magnetic domain patterns observed in the films using magnetic force microscopy.

A refraction correction for buried interfaces applied to in situ grazing-incidence X-ray diffraction studies on Pd electrodes.

In situ characterization of electrochemical systems can provide deep insights into the structure of electrodes under applied potential. Grazing-incidence X-ray diffraction (GIXRD) is a particularly valuable tool owing to its ability to characterize the near-surface structure of electrodes through a layer of electrolyte, which is of paramount importance in surface-mediated processes such as catalysis and adsorption. Corrections for the refraction that occurs as an X-ray passes through an interface have been derived for a vacuum-material interface. In this work, a more general form of the refraction correction was developed which can be applied to buried interfaces, including liquid-solid interfaces. The correction is largest at incidence angles near the critical angle for the interface and decreases at angles larger and smaller than the critical angle. Effective optical constants are also introduced which can be used to calculate the critical angle for total external reflection at the interface. This correction is applied to GIXRD measurements of an aqueous electrolyte-Pd interface, demonstrating that the correction allows for the comparison of GIXRD measurements at multiple incidence angles. This work improves quantitative analysis of d-spacing values from GIXRD measurements of liquid-solid systems, facilitating the connection between electrochemical behavior and structure under in situ conditions.

Searching for New Polymorphs by Epitaxial Growth.

The formation of unknown polymorphs due to the crystallization at a substrate surface is frequently observed. This phenomenon is much less studied for epitaxially grown molecular crystals since the unambiguous proof of a new polymorph is a challenging task. The existence of multiple epitaxial alignments of the crystallites together with the simultaneous presence of different polymorphs does not allow simple phase identification. We present grazing incidence X-ray diffraction studies on conjugated molecules like perylenetetracarboxylic dianhydride (PTCDA), pentacene, dibenzopentacene (trans-DBPen), and dicyanovinylquater-thiophene (DCV4T-Et2) grown by physical vapor deposition on single crystalline surfaces like Ag(111), Cu(111), and graphene. A new method for indexing the observed Bragg peaks allows the determination of the crystallographic unit cells so that the type of crystallographic phase can be clearly identified. This approach even works when several polymorphs are simultaneously present within a single sample as shown for DCV4T-Et2 on Ag(111). Additionally, epitaxial relationships between the epitaxially grown crystallites and the single crystalline surfaces are determined. In a subsequent step, the experimental data are used for the crystal structure solution of an unknown polymorph, as shown for the example trans-DBPen grown on Cu(111).

In Situ Electric-Field Study of Surface Effects in Domain Engineered Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 Relaxor Crystals by Grazing Incidence Diffraction

In this work, we present a grazing incidence X-ray diffraction study of the surface of a 0.24Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) [011] poled rhombohedral single crystal. The near surface microstructure (the top several tens to hundreds of unit cells) was measured in situ under an applied electric field. The strains calculated from the change in lattice parameters have been compared to the macroscopic strain measured with a strain gauge affixed to the sample surface. The depth dependence of the electrostrain at the crystal surface was investigated as a function of temperature. The analysis revealed hidden sweet spots featuring unusually high strains that were observed as a function of depth, temperature and orientation of the lattice planes.

Grazing Incidence X-ray Diffraction Studies of Lipid-Peptide Mixed Monolayers during Shear Flow.

Grazing incidence X-ray diffraction (GIXD) studies of monolayers of biomolecules at an air–water interface give quantitative information of in-plane packing, coherence length of crystalline domains, etc. Rheo-GIXD measurements can reveal quantitative changes in the nanocrystalline domains of a monolayer under shear. Here, we report GIXD studies of monolayers of alamethicin peptide, DPPC lipid, and their mixtures at an air–water interface under steady shear stress. The alamethicin monolayer and the mixed monolayer show a flow jamming transition. On the other hand, the pure 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer under constant stress flows steadily with a notable enhancement of the area/molecule and coherence lengths, suggesting the fusion of nanocrystallites during flow. The DPPC–alamethicin mixed monolayer shows no significant change in the area/DPPC molecule, but the coherence lengths of the individual phases (DPPC and alamethicin) increase, suggesting that the crystallites of individual phases grow bigger by merging of domains. More phase separation occurs in the system during flow. Our results show that rheo-GIXD has the potential to explore in situ molecular structural changes under rheological conditions for a diverse range of confined biomolecules at interfaces.

The impact of β-myrcene – the main component of the hop essential oil – on the lipid films

β-myrcene (myrcene) is the main component of the hop essential oil, the latter being a plant derived extract of a wide range of antimicrobial properties. To get a deeper insight in the role of myrcene in the membrane-related activity of the total extract, in this work the effect of this terpene on the lipid monolayers was investigated. The aim of the studies was to analyze and to compare the influence of myrcene on the one component films formed by the lipids typical of plant and fungi membranes and differing in the structure of both polar and non-polar part of the molecule. The experiments involved the surface pressure-area measurements, the penetration and the relaxation studies, Brewster angle microcopy and Grazing incidence X-ray diffraction (GIXD) studies. It was found that myrcene causes the decrease of the condensation and/or stability and changes the morphology of the lipid monolayers, however its exact effect is determined by the concentration and by the lipid type. Moreover, the mechanisms leading to the alterations within the organization of the film are different depending on the monolayer material and they may involve the extraction of the molecules from the interface and/or accommodation of terpene in the lipid environment. It was also summarized that although myrcene and the hop essential oil affect the properties of the lipid films they act on the studied membranes according to different mechanisms. • β-myrcene changes the fluidity, stability and morphology of the lipid monolayers. • β-myrcene may penetrate into the film or extract the molecules from the interface. • The mechanism of action of β-myrcene and the hop essential oil is different.

Dichlorobiphenyls and chlorinated benzoic acids – Emergent soil pollutants in model bacterial membranes. Langmuir monolayer and Grazing Incidence X-ray Diffraction studies

Abstract The multi-decade worldwide application of polychlorinated biphenyls (PCB) leads to the problem of soil pollution. The production and application of PCB was banned, so the gradual decrease of their concentration in the soils was expected. On the contrary, novel sources of dichlorobiphenyls as PCB 11 were identified and these emergent pollutants are still emitted to the environment. Dichlorobiphenyls and some chlorobenzoic acids (CBA) are known as dead-end PCB metabolites – they accumulate in the soils and being toxic to microorganisms lead to the impoverishment of soil decomposer consortia. The toxicity of PCB and CBA is connected with their membrane activity and accumulation in the bacterial membranes. The correlation between the phospholipid composition of the bacterial membrane and the toxicity of PCB and CBA is unfortunately unknown limiting the effective selection of bacterial species for bioremediation of polluted soils. To shed light on these phenomena we applied binary phospholipid Langmuir monolayers as model bacterial membranes. With these models we studied the phenomena of dichlorobiphenyls and selected CBA molecules' incorporation and the effects exerted by these molecules on the ordering of the phospholipid molecules at the molecular scale. For the studies of the organization of the model membranes we applied Grazing Incidence X-ray Diffraction. It turned out that the model membranes rich in cardiolipin can accumulate more pollutant molecules than the models containing phosphatidylglycerols. The accumulation of the pollutants did not cause any significant changes in the 2D crystalline structure of the former models whereas the latter were profoundly modified.

High-Performance Near-Infrared-Selective Thin Film Organic Photodiode Based on a Molecular Approach Targeted to Ideal Semiconductor Junctions.

A molecular approach to achieve wide linear dynamic range (LDR) and near-infrared (NIR)-selective thin film organic photodiodes (OPDs) with high detectivity is reported. Comparative studies based on two NIR-selective polymers are systematically investigated: the commercially available poly[(4,4'-bis(2-ethylhexyl)cyclopenta[2,1-b:3,4-b']dithiophene)-alt-(benzo[c][1,2,5]thiadiazole)] (PCPDTBT) and the synthesized poly[(4,4'-(bis(hexyldecylsulfanyl)methylene)cyclopenta[2,1-b:3,4-b']-dithiophene)-alt-(benzo[c][1,2,5]thiadiazole)] (PCPDTSBT). The introduction of sp2-hybridized side chains in the PCPDTSBT structure can improve chain planarity and thus intermolecular interactions, as confirmed by Raman spectroscopy and grazing incidence X-ray diffraction studies. The favorable crystalline orientation of PCPDTSBT leads to enhanced photocurrent and suppressed noise current, compared to that of PCPDTBT, followed by a sharp increase in the specific detectivity of PCPDTSBT-based NIR OPDs by 1.54 × 1012 Jones. The physics behind PCPDTSBT is analyzed employing optical simulation, temperature-dependent junction analyses, and Mott-Schottky analysis. Furthermore, it is found that PCPDTSBT possesses an exceptional nonsaturation photocurrent, which leads to a wide LDR of 128 dB. This study shows the possibility of realizing thin film NIR-selective OPDs using synthetic approaches.

Indexing grazing-incidence X-ray diffraction patterns of thin films: lattices of higher symmetry.

Grazing-incidence X-ray diffraction studies on organic thin films are often performed on systems showing fibre-textured growth. However, indexing their experimental diffraction patterns is generally challenging, especially if low-symmetry lattices are involved. Recently, analytical mathematical expressions for indexing experimental diffraction patterns of triclinic lattices were provided. In the present work, the corresponding formalism for crystal lattices of higher symmetry is given and procedures for applying these equations for indexing experimental data are described. Two examples are presented to demonstrate the feasibility of the indexing method. For layered crystals of the prototypical organic semiconductors di-indeno-perylene and (ortho-di-fluoro)-sexi-phenyl, as grown on highly oriented pyrolytic graphite, their yet unknown unit-cell parameters are determined and their crystallographic lattices are identified as monoclinic and orthorhombic, respectively.

Magnetic anisotropy and magnetostrictive properties of sputtered Tb–Dy–Fe–Co thin films

Tb–Dy–Fe–Co thin films grown on Si $$\left\langle {100} \right\rangle$$ substrates at different substrate temperatures viz., room temperature, 300, 400 and 500 °C were investigated for structural, microstructural, magnetic and magnetostrictive properties. Grazing incidence X-ray diffraction studies showed presence of amorphous structure for the as-deposited film. Structural studies further indicated formation of (Tb,Dy)2(Fe,Co)17 and Fe–Co phases for the films grown at higher substrate temperatures. Magnetization measurements displayed presence of strong in-plane magnetic anisotropy for all the films. In addition to this, formation of out-of-plane magnetic anisotropy co-existing with in-plane magnetic anisotropy was noticed for the films grown at higher substrate temperatures. Accordingly, magnetic force microscopy studies indicated a strong out-of-plane magnetic contrast for the films grown at higher substrate temperatures. The magnetostriction estimated from tip deflection measurement was found to be negligibly small for the film grown at intermediate temperature viz., 300 °C. However, with subsequent increase in substrate temperatures the magnetostriction was found to increase. The presence of strong out-of-plane magnetic anisotropy co-existing with in-plane components was found to be detrimental for the development of magnetostriction.