Bulk EuTiO3 is known as a compound in which spin and soft phonon mode is strongly coupled. Recent theoretical study suggests that application of stress or formation of strain leads to a drastic change in magnetic and dielectric properties of EuTiO3 and that so-called multiferroic properties emerge under such a situation. In the present study, effect of strain induced by a substrate, on which EuTiO3 thin film is deposited, on the magnetic properties of the film has been experimentally examined. By using a pulsed laser deposition method, EuTiO3 thin film has been deposited on different kinds of substrate, i.e., LaAlO3, SrTiO3, and DyScO3; the lattice parameter of these compounds is smaller than, just the same as, and larger than that of EuTiO3, respectively. X-ray diffraction analysis confirms that the strain induced in the plane of as-deposited EuTiO3 thin films on different substrates is coincident with the lattice parameter of the substrate compounds. Also, all the as-deposited EuTiO3 thin films manifest elongation of lattice in a direction perpendicular to the film surface. Temperature dependence of magnetization indicates that all the thin films exhibit ferromagnetic behavior at low temperatures. The magnetization at 2 K under a magnetic field of 100 Oe is the highest for EuTiO3 on DyScO3 and the lowest for EuTiO3 on LaAlO3. The experimental result is coincident with the first-principles calculations which predict that ferromagnetic spin configuration becomes more stable as the lattice volume of EuTiO3is increased.

The LaFeO3 and CaFeOX layers are grown using highly dense target prepared by Pechini method, with which accurate growth rate is achieved. Since the LaFeO3demonstrates the obvious RHEED oscillation until the end of growth, constant growth rate, and the step-terraces structure, the LFO is employed as a buffer and/or reference layer to determine the required pulses to deposit the thickness we desire in the superlattice. Superlattices show the clear satellite peaks and Laue oscillation in the XRD spectra as well as the oscillations caused by the film thickness with a flat surface and superstructure with a flat interface in the x-ray reflection spectrum. The streaky RHEED patterns and step-terraces surface are consistent with the results of spectra using x-ray.

Electrical transport and microstructure of interfaces between nm-thick films of various perovskite oxides grown by pulsed laser deposition (PLD) on TiO2- terminated SrTiO3 (STO) substrates are compared. LaAlO3/STO and KTaO3/STO interfaces become quasi-2DEG after a critical film thickness of 4 unit cell layers. The conductivity survives long anneals in oxygen atmosphere. LaMnO3/STO interfaces remain insulating for all film thicknesses and NdGaO3/STO interfaces are conducting but the conductivity is eliminated after oxygen annealing. Medium-energy ion spectroscopy and scanning transmission electron microscopy detect cationic intermixing within several atomic layers from the interface in all studied interfaces. Our results indicate that the electrical reconstruction in the polar oxide interfaces is a complex combination of different mechanisms, and oxygen vacancies play an important role.

Oxide materials for electronics show recently significant progress. Among the most interesting are oxide composite heterostructures made of thin films. They are taking advantage of integration, anisotropy and synergetic concepts leading to new types of devices and functionalities. Remarkable is that, in the last few years, new devices and artificial materials showing new phenomena were demonstrated. At the same time, their synthesis, processing or fabrication is very often by complex, sophisticated, and, hence, by expensive methods. For further industrial implementation, deep understanding of the growth principles and concepts is required. On a higher level, understanding of the bi-directional relationship between the general and particular principles becomes important and deserves much attention. The immediate benefit is that knowledge on growth for one material can be transferred to another one. This may lead for search of less expensive but optimum technological approaches and can also lead to generation of new materials and devices. In our work we have analyzed the relationship between the particular and general growth principles for some oxide multicomponent perovskites. Materials used in our examples are Bi-Sr-Ca-Cu-O and YBa2Cu3O7, (Ca, Sr)CuO2, (Ca, Ba)CuO2 and Bi4Ti3O12. Presented thin films or heterostructures are with c-axis and non-c-axis orientations. We discuss and we review based on our results film-substrate lattice relationships, principles to control the growth mechanism, the morphology/roughness, the uniformity, and the stability domain and inter diffusion aspects.

Bi1.5Zn1Nb1.5O7 (BZN) epitaxial thin films were prepared on Al2O3with a double ZnO buffer layer by pulsed laser deposition. The pole figure analysis and reciprocal space mapping revealed the single crystalline nature of the thin film. The sharp intense spots in the SAED pattern also indicates the highly crystalline nature of BZN thin film. The electrical properties of the as deposited thin films were investigated by patterning an inter digital capacitor (IDC) structure on BZN. A high tunability was observed in this epitaxially grown thin films.

Preparation of the CaTiO3:Pr (CTO:Pr) phosphor thin film on PET substrate was investigated by using the excimer laser-assisted metal organic decomposition(ELAMOD) and photo reaction of nano-particles (PRNP) process. The effects of the substrate material, starting materials, and UV sources on photoluminescence (PL) were investigated. By using the BaTiO3(BTO) nano-particles buffer layer and the CTO: Pr nano-particles as a starting material, CTO: Pr thin film on the PET substrate was successfully obtained by using the KrF laser and excimer lamp irradiation at 25°C. It was found that excimer lamp irradiation is effective for improving the PL of the films.

Biaxially oriented polyethylene terephthalate (PET) films can be bonded directly by oxygen plasma irradiation and low temperature heat press around 100°C. The irradiated films were kept in the atmosphere for six years, yet they can be bonded tightly as well. Dry- and wet-peel tests indicate that two bonding elements can be suggested, hydrogen bonding and chemical bonding. The films are bonded by these two elements at lower temperatures, but by the pure chemical bonding at higher temperatures. FTIR results on the non-irradiated, irradiated and bonded samples indicate that OH and COOH groups are created at the surface, they are responsible for the hydrogen and chemical bondings. Dehydrated condensation reaction is proposed for the chemical bonding. It is briefly mentioned on two origins for the long lifetime of irradiated active surface.

A water-based BaTiO3 precursor solution, suited for ink-jet printing of hetero-epitaxial BaTiO3 layers on LaAlO3 single-crystal substrates was developed. First, a study on the simultaneous stabilization of Ba2+ and Ti4+ions in a neutral, aqueous environment was performed. Thermal analysis of the precursor was used to select appropriate temperature programs and the rheology of the solutions is studied to optimize dipcoating and later ink-jet printing parameters. On both substrates, it was possible to obtain epitaxial layers of about 200 nm thickness after sintering at temperatures above 1000 °C. Currently, we are adapting the thermal program and heating atmosphere in order to reduce the sintering temperatures, decrease the surface roughness and increase density.

We characterize “blisters”, defects observed in multilayer dielectric (MLD) coatings after exposure to acid cleaning procedures. Nanoindentation is used to make site-specific indentations across blisters to measure the mechanical response, especially their compliance under different conditions of loading. Two regions of statistically different mechanical response are identified within a blister defect and compared to the undisturbed regions of the MLD coating. The indentation response of blisters can vary across samples, and we suggest reasons for this variation.

Recent trends in composite research include the development of structural materials with multiple functionalities. In new studies, novel materials are being designed, developed, modified, and implemented into composite designs. Typically, an increase in functionality requires additional material phases within one system. The presence of excessive phases can result in deterioration of individual or overall properties. True multi-functional materials must maintain all properties at or above the minimum operating limit. In this project, samples of Sb-doped SnO2(ATO) sol-gel solutions are used to coat carbon fibers and are heat treated at a temperature range of 200 – 500 °C. Results from this research are used to model the implementation of sol-gel coatings into carbon fiber reinforced multifunctional composite systems. This research presents a novel thermo-responsive sol-gel/ (dopant) combination and evaluation of the actuating responses due to various heat treatment temperatures. While ATO is a well-known transparent conductive material, the implementation of ATO on carbon fibers for infrared thermal reflectivity has not been examined. These coatings serve as actuators capable of reflecting thermal infrared radiation in mid-range and near-range wavelengths (λ). By altering the ATO sol gel thickness and heat treatment temperatures, optimal optical properties are obtained. While scanning electron microscopy (SEM) is used for imaging, electron diffraction spectroscopy (EDS) is used to verify the compounds present in the coatings. Fourier transform infrared (FT-IR) spectroscopy was performed to analyze the reflectivity in the infrared spectra and analyze the crystal structures after heat treatments.

Methane is an important explosive gas, used extensively at the domestic and industrial sites. It is the main constituent of natural gas, which is the main fuel supplied to homes and industries including automobiles. Detection of trace level of methane gas is very important to avoid any accidental explosion due to its leakage and may cause loss of valuable human life and property. The present paper is focused on the development of new sensing material in the form of composites to improve sensitivity, selectivity and stability. Present work shows the enhanced response of SnO2-ZnO composite structures for methane sensing and further increases its sensing response by loading appropriate catalyst on the sensor surface keeping in view of Fermi energy control mechanism and spillover mechanism. A stable sensor response of 77-85 % was obtained for SnO2-ZnO-Pd sensor structure over a wider range of temperature (160-260oC).

The changes are brought in the elemental semiconductors Si and Ge by replacing them with II-VI and III-V binary analogs or their ternary analogs I-III-VI2 chalcopyrides and II-IV-V2 pnictides respectively. Such compounds exhibit transitions from their parent compound in terms of nature of band gaps (Eg) as indirect to direct in addition to the changes in the values of the Eg. These changes have direct consequence in their optical properties with degenerate states being lifted leading to crystal field splitting and so on. The Eg in ternary bulk semiconducting materials is engineered as a function of certain structural parameters such as anion position parameter (u), tetragonal compression parameter (η) through effective alloying. The contributions to Eg due to these effects are studied as band gap anomalies. The present paper discusses the results of the band gap engineering in some of the bulk ABC2(A= Cd; B=Si,Ge,Sn; C= P,As) semiconductors using theoretical methods. The influence of each of A, B and C atom is also discussed. The dependence of morphology of nano semiconducting particles and the band gap on the chemical environment, temperature is reported by us. The confinement energy of a compound which is the difference in energy between the bulk and nano forms is investigated.

ZnO doped with transition metal (TM) thin films were grown by pulsed laser deposition. XRD pattern reveals that all the ZnTMO films have c-axis orientation normal to the substrate. The reciprocal space mapping shows that the crystallinity of ZnTMO film deteriorates at higher doping of TM. All the TM doped ZnO films have transmittance greater than 75% in the visible region. The band gap of the ZnTMO thin films shows red shift on doping with Ni and Cu where as blue shift is observed for Co and Mn which increases with TM concentration. The copper doped ZnO thin film shows green PL emission at 542 nm along with the band edge emission at 385 nm. But other TM doping shows only band edge emission (385nm) and its intensity decreases at higher doping percentage. The presence of non-polar E2high and E2lowRaman modes in thin films indicates that ‘TM’ doping do not alter the wurtzite structure of ZnO. The magnetic studies of the TM doped ZnO shows room temperature ferromagnetism

Ta doped SnO2 (TTO) films prepared on quartz glass substrates at 200 °C were annealed in the air to investigate the annealing effect on the structural, the optical, and the electrical properties. It is shown that the annealing for TTO films resulted in beneficial effect on the electrical resistivity by improving the carrier density and Hall mobility. The lowest resistivity was 1.4 × 10-3Ω cm obtained at 400 °C annealing temperature. The scattering mechanism in TTO films was discussed from the optical and electrical perspectives. The variation in Hall mobility with increasing the annealing temperature may be attributed to the scattering from the ionized and neutral impurities in TTO films.

Nonlinear optical effects are revealed when strong light fields interact with matter. It has been shown that nanomaterials exhibit properties which are very different from the bulk, and in many cases, the nonlinear optical (NLO) efficiency of nanomaterials is found to be higher in comparison. Recently there has been substantial interest in developing novel NLO media for various applications. Even though several organic as well as inorganic materials have been studied in this connection, only a limited number of NLO reports exist for oxide nanomaterials. Therefore, in this paper we present results of NLO measurements recently conducted in our laboratory in three different oxide nanosystems. It is found that oxide nanomaterials are generally robust, and exhibit good NLO efficiencies, which make them potential candidates for photonic and optoelectronic applications.

Tb doped gadolinium fluoride nanophosphors embedded in an aluminosilicate glass matrix is reported for X-ray imaging applications. The nanocomposite scintillators were prepared by a melt-quench method followed by annealing. The GdF3:Tb nanophosphors precipitated within the oxide glass matrix during the processing and their luminescence and scintillation properties were investigated.

In this work, reactive magnetron-sputtered Pb(Zr,Ti)O3thin films were used to fabricate well-ordered nanodot arrays by means of nanosphere lithography (NSL). NSL is based on a two-step etch process by means of, firstly adjusting the diameter of polystyrene spheres in the self-assembled polymeric nanosphere mask using reactive ion etching, and secondly transferring the mask to the substrate by ion milling with adjusted heights. Hence, structures with different aspect ratios can be fabricated.

Piezoresponse force microscopy was used as the inspection tool on both non-patterned and patterned films. Both the topography and polarization out of plane and in plane was deduced in this mode. Grains of nanodots with low aspect ratio form domain structures comparable to domains in non-patterned films. In contrast to that, nanodots with a higher aspect ratio form particular structures. The in-plane amplitude images show mostly a bisectioned domain assembly, while the out-of-plane amplitude images show in some cases more complex structures like “c”-shaped domains or multi-domains around a center domain.

The patterning of the ferroelectric material was shown to affect the formation of ferroelectric domains. The initial polycrystalline, randomly-ordered films are re-oriented and show domain structures depending on nanodisc diameter and aspect ratio. This may enable tailoring of ferroelectric materials in their piezoelectric and pyroelectric properties by patterning.

Synthesis of FeC2O42H2O nano particles was carried out by thermal double decomposition of solutions of oxalic acid dihydrate (C2H2O4 2H2O) and FeSO4 7H2O employing CATA -2R microwave reactor. Structural elucidation was carried out by employing X-ray diffraction, particle size and shape were studied by transmission electron microscopy and nature of bonding was investigated by Optical absorption and near-infrared spectral studies. The powder resulting from this method is possesses distorted rhombic octahedral structure. The particle grain size is about 50 nm. Details of optical transitions are mentioned in terms of energy states.

Carbon nanotubes (CNTs), nanofibers (CNFs) and graphene are promising components for the next generation high performance structural and multi-functional composite materials. One of the largest obstacles to create strong, electrically or thermally conductive CNT/CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of the carbon nanomaterial purification, ultrasound sonication and functionalization are required. We utilized a new approach to grow CNTs/CNFs directly on the surface of matrix, matrix precursor or filler particles. As the precursor matrix and fillers we utilized cement (clinker), copper powder, fly ash particles, soil and sand. Carbon nanomaterials were successfully grown on these materials without additional catalyst. Investigations of the physical properties of the composite materials based on these carbon modified particles revealed enhancement in the mechanical and electrical properties.