213,754 research outputs found

    Mediating exchange bias by Verwey transition in CoO/Fe3O4 thin film

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    We report the tunability of the exchange bias effect by the first-order metal-insulator transition (known as the Verwey transition) of Fe3O4 in CoO (5 nm)/Fe3O4 (40 nm)/MgO (001) thin film. In the vicinity of the Verwey transition, the exchange bias field is substantially enhanced because of a sharp increase in magnetocrystalline anisotropy constant from high-temperature cubic to lowtemperature monoclinic structure. Moreover, with respect to the Fe3O4 (40 nm)/MgO (001) thin film, the coercivity field of the CoO (5 nm)/Fe3O4 (40 nm)/MgO (001) bilayer is greatly increased for all the temperature range, which would be due to the coupling between Co spins and Fe spins across the interface

    Neutron Electric Dipole Moment at Fixed Topology

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    We describe the finite volume effects of CP-odd quantities, such as the neutron electric dipole moment and the anapole moment in the θ\theta-vacuum, under different topological sectors. We evaluate the three-point Green's functions for the electromagnetic current in a fixed non-trivial topological sector in order to extract these CP-odd observables. We discuss the role of zero modes in the CP-odd Green's function and show that, in the quenched approximation, there is a power divergence in the quark mass for CP-odd quantities at finite volume.Comment: 12 pages, revised manuscript to be publishe

    Understanding the different rotational behaviors of 252^{252}No and 254^{254}No

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    Total Routhian surface calculations have been performed to investigate rapidly rotating transfermium nuclei, the heaviest nuclei accessible by detailed spectroscopy experiments. The observed fast alignment in 252^{252}No and slow alignment in 254^{254}No are well reproduced by the calculations incorporating high-order deformations. The different rotational behaviors of 252^{252}No and 254^{254}No can be understood for the first time in terms of β6\beta_6 deformation that decreases the energies of the νj15/2\nu j_{15/2} intruder orbitals below the N=152 gap. Our investigations reveal the importance of high-order deformation in describing not only the multi-quasiparticle states but also the rotational spectra, both providing probes of the single-particle structure concerning the expected doubly-magic superheavy nuclei.Comment: 5 pages, 4 figures, the version accepted for publication in Phys. Rev.
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