다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

We present a review of experimental and theoretical studies of the anomalous Hall effect (AHE), focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical work, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents which originate from spin-orbit coupling. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors, have more clearly established systematic trends. These two developments in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of Berry-phase curvatures and it is therefore an intrinsic quantum mechanical property of a perfect cyrstal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. We review the full modern semiclassical treatment of the AHE together with the more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Finally we discuss outstanding issues and avenues for future investigation.

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Anomalous hall effect

日本物理学会誌及びJournal of the Physical Society of Japanの月刊について

In solid-state materials with strong relativistic spin-orbit coupling, charge currents generate transverse spin currents. The associated spin Hall and inverse spin Hall effects distinguish between charge and spin current where electron charge is a conserved quantity but its spin direction is not. This review provides a theoretical and experimental treatment of this subfield of spintronics, beginning with distinct microscopic mechanisms seen in ferromagnets and concluding with a discussion of optical-, transport-, and magnetization-dynamics-based experiments closely linked to the microscopic and phenomenological theories presented.

Spin Hall effects

Annual review of condensed matter physics

We report the successful passivation of the Mn acceptors in GaMnP upon exposure to a remote dc hydrogen plasma. The as-grown films are non-metallic and ferromagnetic with a Curie temperature of T_C=55K. After hydrogenation the sample resistivity increases by approximately three orders of magnitude at room temperature and six orders of magnitude at 25 K. Furthermore, the hydrogenated samples are paramagnetic, which is evidenced by a magnetization curve at 5 K that is best described by a Brillouin function with g=2 and J=5/2 expected for Mn atoms in the 3d^5 configuration. These observations unambiguously proof that the ferromagnetism is carrier-mediated also in GaMnP.

Suppression of hole-mediated ferromagnetism in GaMnP by hydrogen

Hybrid films composed of lamella forming polystyrene-d8-block-poly(n-butyl methacrylate) (PSd-b-PBMA) diblock copolymer (DBC) and PS-coated maghemite (γ-Fe2O3) nanoparticles (NPs) are investigated. The structure of the hybrid films is systematically probed from the air-polymer interface to the substrate-polymer interface using time-of-flight grazing incidence small angle neutron scattering (TOF-GISANS). The affinity of the PS-coated NPs to the PSd nanodomains results in a well-controlled arrangement of the NPs within the parallel lamella DBC morphology, with a characteristic periodic distance expanding from 45 to 51 nm with progressive increase of NPs upload. In particular, the highly ordered parallel lamella morphology of the hybrid films is maintained at low NP concentrations. At high NP concentrations, the characteristic long-range ordered morphology is lost due to the strong affinity of neighboring NPs to aggregates, forming unguided large sized particle aggregates. The complementary results of real-space characterizations including profilometry, atomic force microscopy, and scanning electron microscopy are consistent with the observation obtained from TOF-GISANS. The potential applications in relation to medical instrumentation and magnetic sensors are highly feasible based on the superparamagnetic behaviors of the fabricated hybrid films, proven with a superconducting quantum interference device magnetometer.

Lamellar Diblock Copolymer Films with Embedded Maghemite Nanoparticles

The remarkable magnetic properties of yttrium iron garnets (YIGs) underpin the use of these materials in a broad scope of spintronic and photonic applications. In particular, the addition of rare earth metals in the structure enhances to a great extent the magneto-optical activity, which is beneficial for the development of nonreciprocal optical devices. Exploiting the wavelength selectivity of magneto-optics, we have identified a range of frequencies at which one can unravel the individual contributions to the magnetism and gyrotropic response arising from cerium and iron. We envision that this outcome may pave the way to further experiments to assess quantitatively the effect on the optical properties of rare earth incorporation into YIG.

/pdf/untangling-the-contributions-of-cerium-and-iron-to-the-4099zfqadw.pdf

Untangling the contributions of cerium and iron to the magnetism of Ce-doped yttrium iron garnet

We describe Raman-scattering experiments in copper-oxide superconductors with transition temperatures between 12 and 90 K as a function of temperature and polarization. The broad continuum observed in all compounds in both the normal and the superconducting state is attributed predominantly to electronic excitations and will be interpreted in terms of charge- carrier fluctuations. The effect of impurities is studied systematically. The limitations of the present theoretical approach as well as possible generalizations are discussed.

Electronic Raman scattering in copper-oxide superconductors and related compounds

We report on the growth of epitaxial ZnO thin films and ZnO based heterostructures on sapphire substrates by laser molecular beam epitaxy (MBE). We first discuss some recent developments in laser-MBE such as flexible ultra-violet laser beam optics, infrared laser heating systems or the use of atomic oxygen and nitrogen sources, and describe the technical realization of our advanced laser-MBE system. Then we describe the optimization of the deposition parameters for ZnO films such as laser fluence and substrate temperature and the use of buffer layers. The detailed structural characterization by x-ray analysis and transmission electron microscopy shows that epitaxial ZnO thin films with high structural quality can be achieved, as demonstrated by a small out-of-plane and in-plane mosaic spread as well as the absence of rotational domains. We also demonstrate the heteroepitaxial growth of ZnO based multilayers as a prerequisite for spin transport experiments and the realization of spintronic devices. As an example, we show that TiN/Co/ZnO/Ni/Au multilayer stacks can be grown on (0001)-oriented sapphire with good structural quality of all layers and well defined in-plane epitaxial relations.

Matthias Opel

Papers

Suppression of hole-mediated ferromagnetism in GaMnP by hydrogen

Lamellar Diblock Copolymer Films with Embedded Maghemite Nanoparticles

Untangling the contributions of cerium and iron to the magnetism of Ce-doped yttrium iron garnet

Electronic Raman scattering in copper-oxide superconductors and related compounds

Laser molecular beam epitaxy of ZnO thin films and heterostructures