Manipulating magnetic and magnetoresistive properties by oxygen vacancy complexes in GCMO thin films.

The effect ofannealing is investigated in GdCaMnO(GCMO) thin films in oxygen and vacuum atmospheres. We show that the reduction of oxygen content in GCMO lattice by vacuum annealing induced more oxygen complex vacancies in both subsurface and interface regions and larger grain domains when compared with the pristine one. Consequently, the double exchange interaction is suppressed and the metallic-ferromagnetic state below Curie temperature turned into spin-glass insulating state.

Tuneable exchange-spring stiffness in amorphous magnetic trilayer structures.

We investigate the magnetic properties of amorphous SmCo/Co(AlZr)/Co(AlZr)exchange-spring magnet trilayers. The magnetically soft Co(AlZr)layer is coupled to the magnetically hard SmColayer through the weakly magnetic low-Co(AlZr)spacer layer. The strength of the coupling can be controlled with temperature and the coupling persists above the intrinsicof the spacer layer due to a long-range magnetic proximity effect.

Tuned AFM-FM coupling by the formation of vacancy complex in GdCaMnOthin film lattice.

The effect ofoxygen and vacuum annealings on the low bandwidth manganite GdCaMnO(GCMO) thin film with= 0.4 was investigated. Based on the magnetic measurements, the AFM-FM coupling is suppressed by the vacuum annealing treatment via destroying the double exchange interaction and increasing the unit cell volume by converting the Mnto the Mn.

Control of the nanosized defect network in superconducting thin films by target grain size.

A nanograined YBCO target, where a great number of grain boundaries, pores etc. exist, is shown to hold an alternative approach to future pulsed laser deposition based high-temperature superconductor thin film and coated conductor technologies. Although the nanograined material is introduced earlier, in this work, we comprehensively demonstrate the modified ablation process, together with unconventional nucleation and growth mechanisms that produces dramatically enhanced flux pinning properties.

Ultrasound irradiation as an effective tool in synthesis of the slag-based catalysts for carboxymethylation.

Waste minimization strategy was applied in the current work for synthesis of the catalysts from industrial solid waste, namely desulfurization slag. The starting slag material comprising CaCO, Ca(OH), SiO, AlO, FeO, and TiO was processed by various treating agents systematically varying the synthesis parameters. A novel efficient technique - ultrasound irradiation, was applied as an additional synthesis step for intensification of the slag dissolution and crystallization of the new phases.

Metastable ferromagnetic flux closure-type domains in strain relaxed GdCaMnOthin films.

We have systematically studied the structural, electrical transport, and magnetic properties of GdCaMnOthin films in function of thickness, which ranged from 22 nm up to 220 nm. We have found that, although no strong substrate-induced strain was detected for any thickness, a sudden change in the electric transport properties was observed when the film thickness increases above 80 nm. While thinner samples are insulating in the whole temperature range, the samples thicker than 80 nm show a clear insulator-to-metal transition (IMT) at around 100 K.

Nuclear Spin Incoherent Neutron Scattering from Quantum Well Resonators.

We report the detection and quantification of nuclear spin incoherent scattering from hydrogen occupying interstitial sites in a thin film of vanadium. The neutron wave field is enhanced in a quantum resonator with magnetically switchable boundaries. Our results provide a pathway for the study of dynamics at surfaces and in ultrathin films using inelastic and/or quasielastic neutron scattering methods.

Concentration dependence of hydrogen diffusion in clamped vanadium (0 0 1) films.

The chemical diffusion coefficient of hydrogen in a 50 nm thin film of vanadium (0 0 1) is measured as a function of concentration and temperature, well above the known phase boundaries. Arrhenius analysis of the tracer diffusion constants reveal large changes in the activation energy with concentration: from 0.10 at 0.

Toward Versatile Sr2FeMoO6-Based Spintronics by Exploiting Nanoscale Defects.

To actualize the high spintronic application potential of complex magnetic oxides, it is essential to fabricate these materials as thin films with the best possible magnetic and electrical properties. Sr2FeMoO6 is an outstanding candidate for such applications, but presently no thin film synthesis route, which would preserve the magnetic properties of bulk Sr2FeMoO6, is currently known. In order to address this problem, we present a comprehensive experimental and theoretical study where we link the magnetic and half metallic properties of Sr2FeMoO6 thin films to lattice strain, Fe-Mo antisite disorder and oxygen vacancies.

Dirty limit scattering behind the decreased anisotropy of doped YBa2Cu3O7-δ thin films.

We measured the resistivity of pulsed-laser-deposited BaCeO3 (BCO)-doped YBCO thin films containing spherical BCO particles in fields up to 30 T. The average diameter of the particles depends on the dopant concentration being below 4 nm in all the samples. Raised values of the upper critical field, Bc2, were observed in all the samples.

The predominance of substrate induced defects in magnetic properties of Sr2FeMoO6 thin films.

A systematic study of epitaxially grown Sr2FeMoO6 thin films on SrTiO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, SrLaAlO4 and MgO single crystal substrates were made.

Giant vortex states in type I superconductors simulated by Ginzburg-Landau equations.

The quantization of magnetic flux in superconductors is usually seen as vortices penetrating the sample. While vortices are unstable in bulk type I superconductors, restricting the superconductor causes a variety of vortex structures to appear. We present a systematic study of giant vortex states in type I superconductors obtained by numerically solving the Ginzburg-Landau equations.

Laccase from Melanocarpus albomyces binds effectively to cellulose.

A laccase from the thermophilic fungus Melanocarpus albomyces was shown to bind to softwood and pure microcrystalline cellulose. The binding isotherm fitted well the Langmuir type one-site binding model. The adsorption parameters indicated that M.

Role of oxidative enzymatic treatments on enzymatic hydrolysis of softwood.

The impact of oxidative modification and partial removal of lignin by laccase-mediator treatments on the enzymatic hydrolysis of steam-pretreated softwood (SPS) was evaluated. Two mediators, N-hydroxy-N-phenylacetamide (NHA) and its acetylated precursor, were oxidized by the laccase from Trametes hirsuta, and their effects on the activity of cellulolytic enzymes and on the hydrolysis yield of SPS were examined. Both simultaneous and sequential combinations of laccase-mediator treatments with commercial cellulases increased the sugar yield in the enzymatic hydrolysis of SPS.

Evaluation of wet oxidation pretreatment for enzymatic hydrolysis of softwood.

The wet oxidation pretreatment (water, oxygen, elevated temperature, and pressure) of softwood (Picea abies) was investigated for enhancing enzymatic hydrolysis. The pretreatment was preliminarily optimized. Six different combinations of reaction time, temperature, and pH were applied, and the compositions of solid and liquid fractions were analyzed.

Adsorption of Trichoderma reesei CBH I and EG II and their catalytic domains on steam pretreated softwood and isolated lignin.

The presence of lignin has shown to play an important role in the enzymatic degradation of softwood. The adsorption of enzymes, and their constituent functional domains on the lignocellulosic material is of key importance to fundamental knowledge of enzymatic hydrolysis. In this study, we compared the adsorption of two purified cellulases from Trichoderma reesei, CBH I (Cel7A) and EG II (Cel5A) and their catalytic domains on steam pretreated softwood (SPS) and lignin using tritium labeled enzymes.

Dynamic interaction of Trichoderma reesei cellobiohydrolases Cel6A and Cel7A and cellulose at equilibrium and during hydrolysis.

The binding of cellobiohydrolases to cellulose is a crucial initial step in cellulose hydrolysis. In the search for a detailed understanding of the function of cellobiohydrolases, much information concerning how the enzymes and their constituent catalytic and cellulose-binding domains interact with cellulose and with each other and how binding changes during hydrolysis is still needed. In this study we used tritium labeling by reductive methylation to monitor binding of the two Trichoderma reesei cellobiohydrolases, Cel6A and Cel7A (formerly CBHII and CBHI), and their catalytic domains.