89 research outputs found

    Continuous Generation of Spinmotive Force in a Patterned Ferromagnetic Film

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    We study, both experimentally and theoretically, the generation of a dc spinmotive force. By exciting a ferromagnetic resonance of a comb-shaped ferromagnetic thin film, a continuous spinmotive force is generated. Experimental results are well reproduced by theoretical calculations, offering a quantitative and microscopic understanding of this spinmotive force.Comment: 4 pages, 4 figures, accepted to Physical Review Letter

    Equation-of-motion approach of spin-motive force

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    We formulate a quantitative theory of an electromotive force of spin origin, i.e., spin-motive force, by the equation-of-motion approach. In a ferromagnetic metal, electrons couple to the local magnetization via the exchange interaction. Electrons feel spin dependent forces due to this interaction, and then the spin-motive force and the anomalous Hall effect appears. We have revealed that the origin of these phenomena is a misalignment between the conduction electron spin and the local magnetization.Comment: 3 pages, 3 figure

    Linear-response theory of spin Seebeck effect in ferromagnetic insulators

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    We formulate a linear response theory of the spin Seebeck effect, i.e., a spin voltage generation from heat current flowing in a ferromagnet. Our approach focuses on the collective magnetic excitation of spins, i.e., magnons. We show that the linear-response formulation provides us with a qualitative as well as quantitative understanding of the spin Seebeck effect observed in a prototypical magnet, yttrium iron garnet.Comment: 6 pages, 3 figures. Added references and revised argument on the length scales at the end of Sec.

    On-The-Fly Observing System of the Nobeyama 45-m and ASTE 10-m Telescopes

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    We have developed spectral line On-The-Fly (OTF) observing mode for the Nobeyama Radio Observatory 45-m and the Atacama Submillimeter Telescope Experiment 10-m telescopes. Sets of digital autocorrelation spectrometers are available for OTF with heterodyne receivers mounted on the telescopes, including the focal-plane 5 x 5 array receiver, BEARS, on the 45-m. During OTF observations, the antenna is continuously driven to cover the mapped region rapidly, resulting in high observing efficiency and accuracy. Pointing of the antenna and readouts from the spectrometer are recorded as fast as 0.1 second. In this paper we report improvements made on software and instruments, requirements and optimization of observing parameters, data reduction process, and verification of the system. It is confirmed that, using optimal parameters, the OTF is about twice as efficient as conventional position-switch observing method.Comment: 11 pages, 13 figures, accepted for publication in PAS

    Spinmotive Force due to Intrinsic Energy of Ferromagnetic Nanowires

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    We study, both analytically and numerically, a spinmotive force arising from inherent magnetic energy of a domain wall in a wedged ferromagnetic nanowire. In a spatially-nonuniform nanowire, domain walls are subjected to an effective magnetic field, resulting in spontaneous motion of the walls. The spinmotive force mechanism converts the ferromagnetic exchange and demagnetizing energy of the nanowire into the electrical energy of the conduction electrons through the domain wall motion. The calculations show that this spinmotive force can be several microvolts, which is easily detectable by experiments.Comment: 4 pages, 2 figure

    Diagnosis of Gastric Cancer in Early Stage — The Clinical Ob­servation of Operated Cases

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    1. An attempt has been made to find the diagnostic criteria for early gastric cancer. It is most important to detect the evidences or suspected features of the malignant growth in incipient stage in order to attain the radical cure by surgical operation. 2. Twelve patients with early gastric cancer (groups A and B) were selected out of 476 patients who had undergone gastrectomy during the past three years in the Okayama Saiseikai General Hospital. The other 6 patients in the &#34;precancerous group&#34; (group C) were also studied, who had abnormal epithelial proliferation in the resected stomach membrane during the same period. 3. The processes of discovery of early cancer have been described. Fairly precise diagnosis can be made in the mucosal carcinoma, but it is not in the ulcer-carcinoma. It was generally difficult to estimate the degree of the malignancy and the extension of the growth preoperatively. 4. The details of the diagnostic aids are as follows. i. Negative occult blood of stool does not always mean the definite diagnostic aid. ii. The malignant gastric change may occur even in non-anacidity. Further investigations should be followed up on gastric ulcer patients if malignant alteration is under the consideration. iii. Minor roentgenological findings, such as the absence or irregularity of mucosal folds, rigid and/or overlapped contour, localized absence or decrease of the peristaltic waves and absence or bow-shaped deformity of the angulus, are of important significance. Such changes should be minutely sought for by X-ray film examination. iv. On gastroscopy and gastrocamera photography, such changes as erosion or irregular granular thickening of the membrane with abnormal reddening and edematous appearance, irregularity of ulcer edge, uneven swelling on ulcer margin with reddening and unsharpness of the edge of adherent coat on ulcer floor, must be noted in the early gastric cancer. v. It is not safe to leave a patient having stomach ulceration under a mere conservative management because it is often quite difficult to dissolve the question of malignancy of the lesion with all sorts of examinations. vi. So far as clinical examinations have indicated malignancy, histological examination must be carried out immediately at the time of operation, even when malignant lesion is absent in inspection and palpation on the exposure of the stomach. vii. On the gross observation of the resected stomach, a particular attention must be paid to erosion, depression or atrophy, irregular granular thickening and abnormal reddening on the restricted areas of the mucosal surface.</p

    Effect of Co Impurities on Superconductivity of FeSe0.4Te0.6 single crystals

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    The effect of Co doping on supercoductivity of FeSe0.4_{0.4}Te0.6_{0.6} single crystals is investigated. The superconducting transition temperature decreases linearly for Co doping with the rate -0.75 K/(Co %). On the other hand, the residual resistivity increase is less than 50 /mu/Omega/mu/Omegacm for 4 % Co doping. These data are consistent with the sign changing interband scattering mechanism of superconductivity (s/pms_/pm symmetry).Comment: 10 pages, 6 figure
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