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

Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin‐dependent electron scattering due to spin canting of the manganese oxide.

31p-S-4 Giant Magnetoresistance in Magnetic Manganese Oxide with Intrinsic Antiferromagnetic Spin Structure

Grain Boundary Complexions

Critical fluctuation of the order parameter in type-ii superconductors.

Manganese oxides (R, A)MnO3 (R = La, Y, Bi or rare earth metal, A = non-trivalent doping element) have been one focus of research for two outstanding properties: (i) conduction electrons (if any) are highly spin-polarized and (ii) competing interactions of several electronic and lattice degrees of freedom lead to extremely rich phase diagrams and complex physics. A better understanding of the latter might result in future technologies using manganites in spin-electronic devices. This review attempts to systematically outline in a phenomenological approach some fundamentals and key experiments on ferromagnetic manganites, partially with respect to thin film structures. Macroscopic magnetic properties (of ferromagnets and glassy manganites) and intrinsic electron transport are described. Preparation and basic properties of thin films, followed by experiments on spin-polarized tunnelling are reviewed. Finally, multiferroic heteroepitaxial film systems of manganites and ferroelectric titanates are addressed, which are promising candidates for significant magnetoelectric phenomena at ambient temperatures.

http://iopscience.iop.org/article/10.1088/0022-3727/39/7/R01/pdf

Ferromagnetic manganites: spin-polarized conduction versus competing interactions

The predictions of Moore's law are considered by experts to be valid until 2020 giving rise to "post-Moore's" technologies afterwards. Energy efficiency is one of the major challenges in high-performance computing that should be answered. Superconductor digital technology is a promising post-Moore's alternative for the development of supercomputers. In this paper, we consider operation principles of an energy-efficient superconductor logic and memory circuits with a short retrospective review of their evolution. We analyze their shortcomings in respect to computer circuits design. Possible ways of further research are outlined.

Beyond Moore's technologies: operation principles of a superconductor alternative.

The microstructure of binary Al100−x–Mgx (x = 10, 15, 18 and 25 wt%) alloys after long anneals (600–4000 h) was studied between 210 and 440 °C. The transition from incomplete to complete wetting of Al/Al grain boundaries (GBs) by the second solid phase Al3Mg2 has been observed. The portion of completely wetted GBs increases with increasing temperature beginning from Twsmin = 220 °C. Above Twsmax = 410 °C all Al/Al GBs are completely wetted by the Al3Mg2 phase.

/pdf/wetting-of-grain-boundaries-in-al-by-the-solid-al3mg2-phase-3od8prwqmu.pdf

Wetting of grain boundaries in Al by the solid Al3Mg2 phase

A chemical deposition technique based on the use of solutions of metal-chelate coordination compounds has been applied to prepare rare-earth–manganite-oxide thin films. La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 thin films have been grown epitaxially on MgO(100) substrates and characterized by structural (x-ray diffraction analysis, atomic force microscopy) and magnetotransport (T=4.2–300 K, and B=0–5 T) measurements.

Preparation of rare-earth manganite-oxide thin films by metalorganic aerosol deposition technique

The origin of the resistive transition broadening of superconducting MgB2 thin films is investigated. Thermally activated flux flow is found to be responsible for the resistivity in the vicinity of the critical temperature. The activation energy for flux motion is observed to have an extraordinary strong dependence on the magnetic field. The results are discussed.

Thermally assisted flux flow in MgB2: strong magnetic field dependence of the activation energy

We present a study of magnetic structures with controllable effective exchange energy for Josephson switches and memory applications. As a basis for a weak link we propose to use a periodic structure composed of ferromagnetic (F) layers spaced by thin superconductors (s). Our calculations based on the Usadel equations show that switching from parallel (P) to antiparallel (AP) alignment of neighboring F layers can lead to a significant enhancement of the critical current through the junction. To control the magnetic alignment we propose to use a periodic system whose unit cell is a pseudo spin valve of structure F1/s/F2/s where F1 and F2 are two magnetic layers having different coercive fields. In order to check the feasibility of controllable switching between AP and P states through the whole periodic structure, we prepared a superlattice [Co(1.5 nm)/Nb(8 nm)/Co(2.5 nm)/Nb(8 nm)]6 between two superconducting layers of Nb(25 nm). Neutron scattering and magnetometry data showed that parallel and antiparallel alignment can be controlled with a magnetic field of only several tens of Oersted.

Anatoli S. Sidorenko

Papers

Beyond Moore's technologies: operation principles of a superconductor alternative.

Wetting of grain boundaries in Al by the solid Al3Mg2 phase

Preparation of rare-earth manganite-oxide thin films by metalorganic aerosol deposition technique

Thermally assisted flux flow in MgB2: strong magnetic field dependence of the activation energy

Periodic Co/Nb pseudo spin valve for cryogenic memory.