1,237 research outputs found

    Lattice structure and magnetization of LaCoO3 thin films

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    We investigate the structure and magnetic properties of thin films of the LaCoO3_{3} compound. Thin films are deposited by pulsed laser deposition on various substrates in order to tune the strain from compressive to tensile. Single-phase (001) oriented LaCoO3_{3} layers were grown on all substrates despite large misfits. The tetragonal distortion of the films covers a wide range from -2% to 2.8%. Our LaCoO3_{3} films are ferromagnetic with Curie temperature around 85 K, contrary to the bulk. The total magnetic moment is below 1μB1\mu_{B}/Co3+^{3+}, a value relatively small for an exited spin-state of the Co3+^{3+} ions, but comparable to values reported in literature. A correlation of strain states and magnetic moment of Co3+^{3+} ions in LaCoO3_{3} thin films is observed.Comment: submitted tu European Phys. J.

    Semimetalic antiferromagnetism in the half-Heusler compound CuMnSb

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    The half-Heusler compound CuMnSb, the first antiferromagnet (AFM) in the Mn-based class of Heuslers and half-Heuslers that contains several conventional and half metallic ferromagnets, shows a peculiar stability of its magnetic order in high magnetic fields. Density functional based studies reveal an unusual nature of its unstable (and therefore unseen) paramagnetic state, which for one electron less (CuMnSn, for example) would be a zero gap semiconductor (accidentally so) between two sets of very narrow, topologically separate bands of Mn 3d character. The extremely flat Mn 3d bands result from the environment: Mn has four tetrahedrally coordinated Cu atoms whose 3d states lie well below the Fermi level, and the other four tetrahedrally coordinated sites are empty, leaving chemically isolated Mn 3d states. The AFM phase can be pictured heuristically as a self-doped Cu1+^{1+}Mn2+^{2+}Sb3−^{3-} compensated semimetal with heavy mass electrons and light mass holes, with magnetic coupling proceeding through Kondo and/or antiKondo coupling separately through the two carrier types. The ratio of the linear specific heat coefficient and the calculated Fermi level density of states indicates a large mass enhancement m∗/m∼5m^*/m \sim 5, or larger if a correlated band structure is taken as the reference

    Expert recommendations to personalization of medical approaches in treatment of multiple sclerosis: an overview of family planning and pregnancy

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    Multiple sclerosis is the most common chronic autoimmune disease of the central nervous system which preferentially affects females at childbearing age. For this reason, patients and treating physicians were frequently confronted with questions concerning family planning, pregnancy and birth. Preventive and personalized treatment approaches are considered, because topics as heredity, risk of congenital malformations, influence of pregnancy on MS and aspects of drug therapy during the period of conception, pregnancy, puerperium and lactation have to be discussed. Here, we provide an overview about the current state of knowledge regarding these issues

    Nonclassical correlations in damped quantum solitons

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    Using cumulant expansion in Gaussian approximation, the internal quantum statistics of damped soliton-like pulses in Kerr media are studied numerically, considering both narrow and finite bandwidth spectral pulse components. It is shown that the sub-Poissonian statistics can be enhanced, under certain circumstances, by absorption, which damps out some destructive interferences. Further, it is shown that both the photon-number correlation and the correlation of the photon-number variance between different pulse components can be highly nonclassical even for an absorbing fiber. Optimum frequency windows are determined in order to realize strong nonclassical behavior, which offers novel possibilities of using solitons in optical fibers as a source of nonclassically correlated light beams.Comment: 15 pages, 11 PS figures (color

    All-fibre source of amplitude-squeezed light pulses

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    An all-fibre source of amplitude squeezed solitons utilizing the self-phase modulation in an asymmetric Sagnac interferometer is experimentally demonstrated. The asymmetry of the interferometer is passively controlled by an integrated fibre coupler, allowing for the optimisation of the noise reduction. We have carefully studied the dependence of the amplitude noise on the asymmetry and the power launched into the Sagnac interferometer. Qualitatively, we find good agreement between the experimental results, a semi-classical theory and earlier numerical calculations [Schmitt etl.al., PRL Vol. 81, p.2446, (1998)]. The stability and flexibility of this all-fibre source makes it particularly well suited to applications in quantum information science
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