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Interface engineering in complex oxide superlattices is a growing field, enabling manipulation of the exceptional properties of these materials, and also providing access to new phases and emergent physical phenomena. Here we demonstrate how interfacial interactions can induce a complex charge and spin structure in a bulk paramagnetic material. We investigate a superlattice (SLs) consisting of paramagnetic LaNiO3 (LNO) and highly spin-polarized ferromagnetic La2/3Ca1/3MnO3 (LCMO), grown on SrTiO3 (001) substrate. We observed emerging magnetism in LNO through an exchange bias mechanism at the interfaces in X-ray resonant magnetic reflectivity. We find non-symmetric interface induced magnetization profiles in LNO and LCMO which we relate to a periodic complex charge and spin superstructure. High resolution scanning transmission electron microscopy images reveal that the upper and lower interfaces exhibit no significant structural variations. The different long range magnetic order emerging in LNO layers demonstrates the enormous potential of interfacial reconstruction as a tool for tailored electronic properties. [ABSTRACT FROM AUTHOR]

Thin ferromagnetic La2/3Ca1/3MnO3 layers are deposited in between two layers of the high-Tc superconductor YBa2Cu3O7–δ (YBCO) by pulsed laser deposition. Using a tailored buffer layer allows the change of the orientation of the CuO2 planes inside the superconducting layers. With this technique it is possible to produce ferromagnetic barrier layers with high ferromagnetic transition temperatures that are thinner than the coherence length of the adjacent superconductors. Magnetization and electric transport measurements suggest that this geometry might be successful for the generation of ferromagnetic Josephson junctions in high temperature superconducting YBCO. [ABSTRACT FROM AUTHOR]

The atomic structures of SrTiO3 (STO)/LaNiO3 (LNO)/STO heterostructure interfaces were investigated by spherical aberration-corrected (CS) (scanning) transmission electron microscopy. Atomic displacement and lattice distortion measurements and electron energy loss spectroscopy (EELS) were used to quantitatively analyze the distortion of the interfacial octahedra and the bond length at the interfaces. Combined with high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy analyses, two distinct interfacial atomic terminating layers are unambiguously determined. Ensuing quantitative HRTEM measurements revealed that the Ni-O bond length in the interfacial octahedral is elongated at the bottom interface (–NiO2-SrO–). Atomic displacement shows structural relaxation effects when crossing the interfaces and lattice distortions across the interface is more pronounced in LNO than in STO. The Ti/O atomic ratio, La and Ti relative atomic ratio as derived by EELS quantification indicate non-stoichiometric composition at the interfaces. Distinct fine structures of Ti-L2,3 edge and O-K edge at the bottom and top interfaces are observed. By comparison, we are able to estimate Ti valency at both interfaces. Combining the structural distortions and Ti valency, the polar discontinuity and charge transfer at the interfaces are discussed. [ABSTRACT FROM AUTHOR]

Copper oxide CuO/tetragonal CuFe 2 O 4 nanocomposites have been synthesized via the simple microemulsion route by addition of different Fe 3+ ion ratios (where Fe 3+ content=0, 0.05, 0.10, 0.15 and 0.20). It is clear that the pure CuO phase was observed from the precipitated copper hydroxide precursor at pH 12 as prepared and annealed at 600 to 800 °C for 2 h. Meanwhile, Fe 3+ addition at low substitution concentration (0.05) was indexed pure CuO phase. Further enhancing the Fe 3+ up to different concentration from 0.10 to 0.20 was confirmed CuO/t-CuFe 2 O 4 nanocomposites. The ratio of t-CuFe 2 O 4 phase in the composite was increment with increasing the Fe 3+ addition. It was increased up to 28% by addition of Fe 3+ content of 0.20 and annealed at 800 °C for 2 h. Indeed, the crystallite size and the theoretical density calculated from XRD pattern were decreased whereas the unit cell volume was increased as the result of Fe 3+ -addition. The microstructures of the produced pure CuO powders were exhibited pseudo-cubic like structure whereas they were appeared as spherical like structure by addition of Fe 3+ ion. Ultraviolet-visible spectrum revealed that three strong band transitions were assigned in the range of 450–950 nm, characteristics to the iron substitution. Of note, the band gap energies of pure and CuO/t-CuFe 2 O 4 powders were in the range from 1.38 to 1.47 eV. Otherwise, magnetic properties evinced that pure CuO particles have weak ferromagnetic characteristics. Furthermore, the magnetic properties were enhanced with increasing the Fe 3+ addition corresponding to increase t-CuFe 2 O 4 phase content. [ABSTRACT FROM AUTHOR]

We have used the pulsed laser deposition (PLD) technique followed by post-annealing process with magnesium vapor at 700C for 30 min to grow a high-quality CrO/MgB bilayer prepared on AlO (1102) single crystal. The X-ray diffraction patterns showed high-quality orientated growth of MgB phase. The obtained films were approximately 300 nm thick and had lateral dimensions of 5×5 mm. SQUID magnetometry, magneto-optical Faraday microscopy, and magneto-transport techniques were used in order to measure the critical current density (J) that was found to be 7- 9×10 A/cm at 15 K. Transition temperature (T) for the films was ∼37 K. The obtained magnetic hysteresis loops at low temperatures exhibited asymmetry with respect to H = 0. This can be explained in terms of pinning of flux lines in the films due to magnetic interaction with the ferromagnetic CrO layer. [ABSTRACT FROM AUTHOR]

Abstract: Mn-doped ZnS nanocrystalline thin films having composition Zn1−x Mn x S (x=0.02, 0.05, 0.1 and 0.15) were prepared by the electron beam evaporation technique. Their structural and magnetic properties had been investigated. X-ray diffraction results show single phase of hexagonal type structure samples without any detectable secondary phase providing the evidence that Mn2+ ions are incorporated into the ZnS lattice. Evidence of nanocrystalline nature of the films was observed from the investigation of surface morphology using atomic force microscopy. The magnetic measurements at 5K reveal superparamagnetic behavior. The field dependent magnetization measurements confirm the absence of the room temperature ferromagnetism in the single phase electron beam evaporated Zn1−x Mn x S (x=0.02, 0.05, 0.1 and 0.15) nanocrystalline films. Furthermore, the inverse susceptibility versus T confirms paramagnetic behavior for the Mn-doped films in the temperature range 100K≤T≤300K. The absence of significant impurities and/or defects could be attributed to explanation for the absence of free carriers and consequently the absence of room temperature ferromagnetism in all nanocrystalline Zn1−x Mn x S films. The absence of room temperature ferromagnetism is evidence by marked concave nature of Arrott''s plot without any spontaneous magnetization. [Copyright &y& Elsevier]

Abstract: Epitaxial superlattices of half-metal, colossal magnetoresistive La2/3Ca1/3MnO3 (HM-CMR) and high-T c superconducting YBa2Cu3O7−δ (HTSC) are prepared on single-crystalline substrate by pulsed laser deposition. Transport measurements R(T) at a superconducting layer of these hybrids exhibit features of both of the constituents of the superlattice. Additionally, below T =35K, far below the superconducting transition temperature a reentrance into a resistive state can be observed. [Copyright &y& Elsevier]

Heterostructures consisting of ferromagnetic La2/3Ca1/3MnO3 and superconducting YBa2Cu3O7-x layers were fabricated by conventional pulsed laser deposition in conjunction with shadow mask techniques to define appropriate sample geometries. Using standard dc- four probe measurements we observe a 2% decrease of Tc for injection current densities of 5.10-2 A/cm2 in the case of unpolarized quasiparticles whereas highly spin polarized quasiparticles show a much stronger decrease of 14%. This result clearly demonstrates that the spin plays a crucial role in the Tc reduction. The results are discussed within the frame of a theoretical model based on the Owen-Scalapino approach for nonequilibrium effects in superconductors. [ABSTRACT FROM AUTHOR]

Abstract: We report detailed transport studies on ferromagnet-superconductor heterostructures. Epitaxial heterostructures of half-metal colossal magnetoresistive La2/3Ca1/3MnO3 (HM-CMR) and high T c superconducting YBa2Cu3O7 (YBCO) are grown on SrTiO3 (100) single crystal substrates by pulsed laser deposition. Using the HM–CMR layer as source for spin-polarized quasiparticles, we show the effect of injection of spin-polarized quasiparticles into the ab-plane and along the c-axis of YBCO. The results show a drop in the ab-plane resistance R ab (T) in the case of injection along the c-axis that is discussed to be related to the opening of a pseudogap. [Copyright &y& Elsevier]

We report a systematic study of the strain effect on thin films of nonsuperconducting PrBa2Cu3O7−δ produced by pulsed laser deposition. The transport properties and the Raman active modes are studied for high-quality PrBa2Cu3O7−δ thin films grown on SrTiO3 (1 0 0) under a tensile strain, and under a compression strain on LaSrAlO4 (0 0 1) substrate. The data show a lowering of the polaron binding energy for the samples under compressive strain, as the film thickness decreases. This can be directly concluded from the behavior of the Raman active modes. These modes show a shift of the stretching modes, shifted to lower wave number (cm−1) under the tensile strain, and to higher wave number, under compressive strain. Our results are analyzed in terms of the Fehrenbacher and Rice-model. [Copyright &y& Elsevier]

We have investigated the magnetic properties of Fe doped Cd1-xFexS diluted magnetic semiconducting nanocrystalline thin films for different doping concentrations (0.05 ≤ x ≤ 0.2) synthesized by electron beam evaporation technique. X-ray diffraction patterns confirm the existence of single phase nature in all the Fe doped Cd1-xFexS samples with hexagonal wurtzite type structure with a strong (002) preferred orientation. Evidence of nanocrystalline nature of the films was observed from the investigation of surface morphology using scanning electron microscopy and atomic force microscopy. Magnetic domains were observed by using magnetic force microscopy at room temperature indicating the existence of ferromagnetism over the film surface. The temperature and field dependent magnetization measurements by using superconducting quantum interference device showed ferromagnetic behavior between room temperature and low temperature (5 K) with a Tc at or above room temperature for the nanostructure samples with 0.1 ≤ x ≤ 0.2. The saturation magnetization for Cd1-xFexS system is found to increase with the dopant concentration (x). The exchange interaction between local spin polarized electrons (Fe3+ ions) and conductive electrons according to Ruderman-Kittel-Kasuya-Yosida mechanism, rather than from the Fe oxide impurities, is proposed to be the possible mechanism for ferromagnetism. These results show that the Fe-doped CdS nanocrystalline films can be employed in the fabrication of the nanoscale magnetic device. [ABSTRACT FROM AUTHOR]

Abstract: We report detailed transport studies on ferromagnet-superconductor heterostructures. Epitaxial heterostructures of half-metal colossal magnetoresistive La2/3Ca1/3MnO3 (HM-CMR) and high-T c superconducting YBa2Cu3O7−δ (HTSC) are grown on SrTiO3 (100) single crystal substrates using pulsed laser deposition. Using the HM-CMR layer as source for spin-polarized quasiparticles, we show the effect of injection of spin-polarized quasiparticles into the ab-plane and along the c-axis in the normal state of YBCO. The results show a drop in the ab-plane resistance R ab (T) in the case of injection along the c-axis that is discussed to be related to the opening of a spin-gap in the superconductor. [Copyright &y& Elsevier]

Quantitative magnetooptical measurements have been used to investigate the critical current density in epitaxially grown bilayers of La2/3Ca1/3MnO3 and YBa2Cu3O7-δ. The experiments show that the current density in the superconducting film is strongly supressed due to the adjacent ferromagnetic layer. Additionally it is found that the magnetization state of the ferromagnet influences the critical current density in the superconductor. [Copyright &y& Elsevier]

The genetic parameters, eigenvalues in principal components, correlation, and path coefficient in Egyptian rice (Oryza sativa L.) proceeded to understand the interrelationship among studied traits, which helps develop selection strategies in genetic breeding programs under aerobic conditions. Twelve rice genotypes planted under the aerobic condition in a randomized complete block design included three replications during the 2020 and 2021 seasons. The analysis of variance revealed significant differences among studied genotypes, indicating a broad genetic diversity among its genotypes. Eigenvalues used helped to understand the data structure and trait relations and divided the 21 traits into two components. The highly positive phenotypic and genotypic correlations appeared in 16 characteristics, i.e., leaf area index, total chlorophyll, and antioxidant traits, indicating that any improvement of these traits will improve rice grain yield under aerobic conditions. The path structure showed that panicle weight, the number of panicles hill-1, catalase, superoxide dismutase, root length, and flag leaf area had increased grain yield. The current results indicated that Egyptian hybrid1, GZ9399, and Giza179 could recommend for cultivation under aerobic conditions and serve as donors in breeding programs to improve tolerance to drought under aerobic conditions. [ABSTRACT FROM AUTHOR]

During illumination of the MgB 2 :Cr 2 O 3 films it was established substantial spectral shift of the infrared spectra in the vicinity of 20–50 cm −1 . The excitations were performed by nanosecond Er:glass laser operating at 1.54 μm and by microsecond 10.6 μm CO 2 laser. The spectral shifts of the IR maxima were in opposite spectral directions for the two types of lasers. This one observed difference correlates well with spectral shift of their critical temperatures. The possible explanation is given by performance of DFT calculations of the charge density redistribution and the time kinetics of the photovoltaic response. To understand the kinetics of the photoinduced processes the time kinetics of photoresponse was done for the particular laser wavelengths. [ABSTRACT FROM AUTHOR]

Epitaxial bilayers of the high-temperature-superconductor YBa 2 Cu 3 O 7 − δ (YBCO) and the ferromagnetic metal La 0.67 Ca 0.33 MnO 3 (LCMO) were prepared by pulsed laser deposition on (1 1 0)-oriented SrTiO 3 substrates, such that the CuO 2 planes of YBCO are perpendicular to the YBCO–LCMO interface. X-ray diffraction and Raman scattering demonstrate complete (1 1 0) orientation of both YBCO and LCMO overlayers. The resistivity and magnetization of the bilayer films are highly anisotropic. The critical temperatures for superconductivity and ferromagnetism as well as the saturation magnetization exhibit modest reductions compared to corresponding bulk values. [ABSTRACT FROM AUTHOR]

Highlights: [•] Photoinduced enhancement of critical temperature in MgB2–Cr2O3 films was found. [•] Crucail role of electron–phonon interacton was shown. [•] Optimal ratio fundamental/SHG intensities was varied within 4:1 and 6:1. [Copyright &y& Elsevier]

Please cite this paper as: Taher S, Inder J, Soltan S, Eliahoo J, Edmonds D, Bennett P. Prostaglandin E2 vaginal gel or tablets for the induction of labour at term: a randomised controlled trial. BJOG 2011;118:719-725. To compare the effectiveness of prostaglandin E2 (dinopristone) vaginal gel versus vaginal tablets for the induction of labour at term. Randomised controlled clinical trial. University maternity hospital in London. Pregnant women with cephalic presentation undergoing induction of labour after 37 weeks of gestation. Prostaglandin E2 vaginal tablets (3 mg) or vaginal gel (1 mg/2 mg) was administered at 6-hourly intervals until the cervix was suitable for amniotomy. Induction to delivery interval, in minutes; rate of failed induction of labour requiring caesarean delivery. Eighty-two women received prostaglandin gel; 83 women received vaginal tablets. There were significant differences between the two treatment groups in the primary outcomes. The mean induction to delivery interval was significantly shorter in women who received the gel (1400 minutes, 690-2280 minutes, versus 1780 minutes, 960-2640 minutes; P = 0.03). The rate of failed induction of labour was significantly higher in women who received tablets (10.84 versus 1.22%; P = 0.01). Subanalysis showed that these differences were only representative of differences in the groups of primigravid women. There were no significant differences in any of the secondary outcomes, including the number of women who required syntocinon augmentation, the rate of uterine hyperstimulation, the need for epidural analgesia, meconium staining of liquor, the need for fetal blood sampling, or delivery by caesarean section. There were no differences in adverse maternal and neonatal outcomes. Prostaglandin E2 vaginal gel is superior to vaginal tablets for the induction of labour. [ABSTRACT FROM AUTHOR]

Hybrid systems of thin films of oxide ferromagnets and hightemperature superconductors have been investigated by scanning Hall probe microscopy (SHPM) to analyze the local magnetic flux density distribution at low temperatures. In addition to the intrinsic properties of the films themselves, such structures exhibit novel phenomena due to complex interactions arising at the interface between them. The latter can be divided into processes originating from either electronic or magnetic coupling, respectively. As a direct consequence, the distribution of vortices in the superconductor is strongly influenced by the magnetic background arising from the ferromagnet. The local magnetic information obtained from SHPM images provides clear evidence for the presence of a magnetic dipolar interaction between the magnetic domains of the ferromagnetic component and the vortex ensemble in the superconductor. [ABSTRACT FROM AUTHOR]

A heterostructure comprised of a 2.7 nm (7 unit cell) thick layer of the metallic ferromagnet La2/3Ca1/3MnO3 and two 50 nm thick layers of the high-temperature superconductor YBa2Cu3O7 epitaxially grown on (100) SrTiO3 by pulsed-laser deposition was characterized by magnetization measurements and spherical-aberration-corrected high-resolution transmission electron microscopy (HRTEM). The saturation magnetization is about half of that in bulk La2/3Ca1/3MnO3. A massive reduction in the magnetization previously inferred from sputter-deposited La2/3Ca1/3MnO3–YBa2Cu3O7 heterostructures can be ruled out. HRTEM image analysis, combined with image simulation and a focus series reconstruction, revealed atomically sharp epitaxial structures with stacking sequences –(La,Ca)O–CuO2– and –BaO–MnO– at the top and bottom interface. [ABSTRACT FROM AUTHOR]

In this work, we comparatively investigated two MgB2 films: one (F1) was typically fabricated using the PLD method, while the other (F2) was fabricated using the same method but on top of a 100-nm-thick CrO2 layer. Both films had a thickness of 300 nm and were annealed ex situ at 700 °C for 30 min before being investigated under an external magnetic field of up to ± 7 T. The activation energy (Uo), upper critical field (HC2), irreversibility field (Hirr), magnetoresistance (MR), and I-V characteristics for the two films were studied in detail, and the results were compared with theoretical models. XRD analysis showed that both films are c-axis-oriented, while the RRR values for the films were found to be 1.6 and 1.89, respectively. Experimental data showed a broadening of the R-T transitions for an increasing magnetic field, with such broadening observed to be wider for F2 due to surface superconductivity. The activation energy under magnetic fields ranging from 0 to 7 T was calculated using our data and compared with a theoretical model. In both films, Uo followed a parabolic curve but was higher for F2 up to 6 T before sharply decreasing, while it continued to follow the same trend for F1 up to 7 T. The theoretical model was in good agreement with F1 for the full span of magnetic fields used. HC2 and Hirr were estimated and fitted using Ginzburg–Landau theory, but although the fitting was very good for F1, some modification in fitting parameters was required to obtain the same fitting for F2. Magnetoresistance and I-V characteristics confirm that the CrO2 layer in F2 leads to faster damage to the superconductivity property for high magnetic fields and temperatures. [ABSTRACT FROM AUTHOR]

In type-II superconductors at T = 0 the critical current density is determined by the pinning of flux lines. Considering an arbitrarily shaped energy landscape the pinning force at each pinning site is given by the derivative of the flux line energy with respect to the considered direction. At finite temperatures, in addition, thermal activation can lead to a depinning of flux lines. The governing property in this case is the depth of the corresponding pinning potential, i.e. the pinning energy. We show a detailed analysis of both pinning forces and pinning energies of MgB 2 films with inhomogeneous microstructure. We show that a pronounced increase of the pinning energy is responsible for the significantly enhanced stability of the dissipation-free current transport in thin inhomogeneous MgB 2 films. This is found even if the corresponding pinning forces are small. [ABSTRACT FROM AUTHOR]

The calculations of the photoinduced nonlinear optical shift with respect to critical temperature for the MgB 2 superconducting films (pure and doped by Cr) were performed using the first principle quantum chemical simulations. The principal role of the nano-interfaces between the MgB 2 and Cr 2 O 3 was established, and the nano-interfaces have a thickness varying within the 20–30 nm. The latter was done taking into account their long-range ordering additionally aligned by bicolour optical poling. The bicolour poling was performed by the fundamental 10.6 μm laser beam and its doubled frequency coherent second harmonic generation signal. The so formed internal dc-electric field has introduced additional polarization to the media which re-scale the factor of the electron–phonon interaction including the anharmionic one responsible for the occurrence of charge density non-centrosymmetry and the related second order nonlinear optical response. The simulations of the IR induced bicolour treatment were performed both for pure as well as MgB 2 superconducting films doped by Cr 3+. [ABSTRACT FROM AUTHOR]

Abstract: Surface morphology and superconducting properties of MgB2 superconducting thin films prepared by ex-situ annealing of multilayer Mg/B precursors in Mg vapor are studied. Depending on the precursor structure different physical and microstructural properties of the superconductor evolve. Structure and composition of the films are analyzed by scanning electron microscopy and wavelength dispersive x-ray spectroscopy. It is found that certain precursor structures can lead to high quality superconducting films, however, in specific precursor structures mechanical stress leads to the formation of wrinkles strongly affecting the superconducting homogeneity of the films. A correlation between microstructure and superconducting properties, such as pinning or critical current density, can be provided via magneto-optical Faraday microscopy. [Copyright &y& Elsevier]

The electron-phonon interaction is of central importance for the electrical and thermal properties of solids, and its influence on superconductivity, colossal magnetoresistance and other many-body phenomena in correlated-electron materials is the subject of intense research at present. However, the non-local nature of the interactions between valence electrons and lattice ions, often compounded by a plethora of vibrational modes, presents formidable challenges for attempts to experimentally control and theoretically describe the physical properties of complex materials. Here we report a Raman scattering study of the lattice dynamics in superlattices of the high-temperature superconductor YBa2Cu3O7 (YBCO) and the colossal-magnetoresistance compound La2/3Ca1/3MnO3 that suggests a new approach to this problem. We find that a rotational mode of the MnO6 octahedra in La2/3Ca1/3MnO3 experiences pronounced superconductivity-induced line-shape anomalies, which scale linearly with the thickness of the YBCO layers over a remarkably long range of several tens of nanometres. The transfer of the electron-phonon coupling between superlattice layers can be understood as a consequence of long-range Coulomb forces in conjunction with an orbital reconstruction at the interface. The superlattice geometry thus provides new opportunities for controlled modification of the electron-phonon interaction in complex materials. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic measurements on a ferromagnet/insulator/superconductor (La2/3Ca1/3MnO3/SrTiO3/YBa2Cu3O7−x ) structures were performed with the field applied parallel to the plane of the film. We observed an evidence of a modification of the ferromagnetic domain structure in the magnetic layer induced by the superconducting transition in the neighboring superconducting YBa2Cu3O7−x layer. [Copyright &y& Elsevier]

Abstract: Magnetic measurements on a La2/3Ca1/3MnO3/YBa2Cu3O7/La2/3Ca1/3MnO3 trilayer were performed with the field applied parallel to the plane of the film. Ferromagnetic transition is at about 125K and the superconducting transition was suppressed to 60K. The thicknesses of LCMO and YBCO layers were 50nm and 20nm, respectively. We observed an evidence for the ferromagnetic-like interaction between the two LCMO layers. We proposed a coupling mechanism mediated by London screening currents to explain our observations. [Copyright &y& Elsevier]