Magnetic and spectral properties of multi-sublattice oxides SrY2O4:Er3+ and SrEr2O4

SrEr2O4 is a geometrically frustrated magnet which demonstrates rather unusual properties at low temperatures including a coexistence of long- and short-range magnetic order, characterized by two different propagation vectors. In the present work, the effects of crystal fields (CF) in this compound containing four magnetically inequivalent erbium sublattices are investigated experimentally and theoretically. We combine the measurements of the CF levels of the Er3+ ions made on a powder sample of SrEr2O4 using neutron spectroscopy with site-selective optical and electron paramagnetic resonance measurements performed on single crystal samples of the lightly Er-doped nonmagnetic analogue, SrY2O4. Two sets of CF parameters corresponding to the Er3+ ions at the crystallographically inequivalent lattice sites are derived which fit all the available experimental data well, including the magnetization and dc susceptibility data for both lightly doped and concentrated samples.Comment: 14 pages, 9 figure

Magnetic anisotropies and its optical manipulation in epitaxial bismuth ferrite/ferromagnet heterostructure

© 2018 Elsevier B.V. Exchange-coupled BiFeO3/ferromagnet thin film heterostructures are promising for a fast and power efficient control of magnetization of the ferromagnetic layer. In the paper, the results of the study of magnetic properties of the epitaxial Fe2B/BiFeO3heterostructure on (0 0 1)-SrTiO3substrate with ferromagnetic resonance (FMR) spectroscopy are presented. The hierarchy of magnetic anisotropies that determine the angular variation of the resonance field in-plane and in-/out-of the plane of the system include the tetragonal four-fold and uniaxial terms for the Fe2B layer, uniaxial term for antiferromagnetic BiFeO3layer and the exchange coupling at the interface. We find out that the exchange bias direction can be switched by a strong enough applied magnetic field. Both the exchange bias and an in-plane FMR resonance field of the heterostructure are strongly affected by the illumination with λ = 405 nm light. An optical tunability of the exchange bias and ferromagnetic resonance fields of the heterostructure has been demonstrated

Athlome Project Consortium: a concerted effort to discover genomic and other "omic" markers of athletic performance.

Despite numerous attempts to discover genetic variants associated with elite athletic performance, injury predisposition, and elite/world-class athletic status, there has been limited progress to date. Past reliance on candidate gene studies predominantly focusing on genotyping a limited number of single nucleotide polymorphisms or the insertion/deletion variants in small, often heterogeneous cohorts (i.e., made up of athletes of quite different sport specialties) have not generated the kind of results that could offer solid opportunities to bridge the gap between basic research in exercise sciences and deliverables in biomedicine. A retrospective view of genetic association studies with complex disease traits indicates that transition to hypothesis-free genome-wide approaches will be more fruitful. In studies of complex disease, it is well recognized that the magnitude of genetic association is often smaller than initially anticipated, and, as such, large sample sizes are required to identify the gene effects robustly. A symposium was held in Athens and on the Greek island of Santorini from 14-17 May 2015 to review the main findings in exercise genetics and genomics and to explore promising trends and possibilities. The symposium also offered a forum for the development of a position stand (the Santorini Declaration). Among the participants, many were involved in ongoing collaborative studies (e.g., ELITE, GAMES, Gene SMART, GENESIS, and POWERGENE). A consensus emerged among participants that it would be advantageous to bring together all current studies and those recently launched into one new large collaborative initiative, which was subsequently named the Athlome Project Consortium

Magnetic anisotropies and its optical manipulation in epitaxial bismuth ferrite/ferromagnet heterostructure

© 2018 Elsevier B.V. Exchange-coupled BiFeO3/ferromagnet thin film heterostructures are promising for a fast and power efficient control of magnetization of the ferromagnetic layer. In the paper, the results of the study of magnetic properties of the epitaxial Fe2B/BiFeO3heterostructure on (0 0 1)-SrTiO3substrate with ferromagnetic resonance (FMR) spectroscopy are presented. The hierarchy of magnetic anisotropies that determine the angular variation of the resonance field in-plane and in-/out-of the plane of the system include the tetragonal four-fold and uniaxial terms for the Fe2B layer, uniaxial term for antiferromagnetic BiFeO3layer and the exchange coupling at the interface. We find out that the exchange bias direction can be switched by a strong enough applied magnetic field. Both the exchange bias and an in-plane FMR resonance field of the heterostructure are strongly affected by the illumination with λ = 405 nm light. An optical tunability of the exchange bias and ferromagnetic resonance fields of the heterostructure has been demonstrated

Conventional, pulsed and high-field electron paramagnetic resonance for studying metal impurities in calcium phosphates of biogenic and synthetic origins

© 2018 Elsevier B.V. Calcium phosphates (CaP) based materials are widely recognized as the most suitable matrix for bone tissue engineering. The cationic and anionic substitutions of CaP structure by the elements and groups of biological importance seem to be the effective ways to improve the properties of CaP-based substances to achieve the material's desired parameters. Various analytical and biochemical methods are used for controlling their chemical content, structure, morphology, etc. Unfortunately, magnetic resonance techniques are usually not even considered as necessary tools for CaP inspection. Some aspects of application of the commercially realized electron paramagnetic resonance (EPR) approaches for characterization of CaP powders and ceramics (including the nanosized materials) such as hydroxyapatite and tricalcium phosphates of biogenic and synthetic origins containing intrinsic impurities or intentional dopants are demonstrated. Among them (1) conventional approaches; (2) high-frequency approaches – for measuring small amount of material; (3) pulsed methods – to study size effects, effects of the co-doping by different sorts of ions, to determine the location of paramagnetic centers, etc. The key features and advantages of the EPR techniques for CaP based materials characterization that could complement the data obtained with the recognized analytical methods are stressed

Conventional, pulsed and high-field electron paramagnetic resonance for studying metal impurities in calcium phosphates of biogenic and synthetic origins

© 2018 Elsevier B.V. Calcium phosphates (CaP) based materials are widely recognized as the most suitable matrix for bone tissue engineering. The cationic and anionic substitutions of CaP structure by the elements and groups of biological importance seem to be the effective ways to improve the properties of CaP-based substances to achieve the material's desired parameters. Various analytical and biochemical methods are used for controlling their chemical content, structure, morphology, etc. Unfortunately, magnetic resonance techniques are usually not even considered as necessary tools for CaP inspection. Some aspects of application of the commercially realized electron paramagnetic resonance (EPR) approaches for characterization of CaP powders and ceramics (including the nanosized materials) such as hydroxyapatite and tricalcium phosphates of biogenic and synthetic origins containing intrinsic impurities or intentional dopants are demonstrated. Among them (1) conventional approaches; (2) high-frequency approaches – for measuring small amount of material; (3) pulsed methods – to study size effects, effects of the co-doping by different sorts of ions, to determine the location of paramagnetic centers, etc. The key features and advantages of the EPR techniques for CaP based materials characterization that could complement the data obtained with the recognized analytical methods are stressed

Dissolution pour justes motifs. Dissensions entre associés, Inexécution d'obligations contractuelles, Mise en cause de l'objet social

International audience(Paris, 2e Ch. B, 30 oct. 1992, Sté Siri c/ Sté Getrim Cinq et Sté Etude Strichard