反強磁性ホイスラー合金Ni2MnAlおよびMn2VAlを用いた交換バイアス特性

要約のみTohoku University高梨弘毅課

Relationship Between Personality Patterns and Harmfulness : Analysis and Prediction Based on Sentence Embedding

This paper hypothesizes that harmful utterances need to be judged in the context of whole sentences, and the authors extract features of harmful expressions using a general-purpose language model. Based on the extracted features, the authors propose a method to predict the presence or absence of harmful categories. In addition, the authors believe that it is possible to analyze users who incite others by combining this method with research on analyzing the personality of the speaker from statements on social networking sites. The results confirmed that the proposed method can judge the possibility of harmful comments with higher accuracy than simple dictionary-based models or models using a distributed representation of words. The relationship between personality patterns and harmful expressions was also confirmed by an analysis based on a harmful judgment model

Fabrication of magnetic tunnel junctions with a metastable bcc Co3Mn disordered alloy as a bottom electrode

We fabricated MgO barrier magnetic tunnel junctions (MTJs) with a Co3Mn alloy bottom and FeCoB top electrodes. The (001)-oriented epitaxial films of the metastable bcc Co3Mn disordered alloys obtained showed saturation magnetization of approximately 1640 emu/cm3. The transmission electron microscopy showed that the MgO barrier was epitaxially grown on the Co3Mn electrode. Tunnel magnetoresistance of approximately 150% was observed at room temperature after the annealing of MTJs at 350◦C, indicating that bcc Co3Mn alloys have relatively high spin polarization

Spectral Decomposition of Path Space in Solvable Lattice Model

We give the {\it spectral decomposition} of the path space of the U_q(\hatsl) vertex model with respect to the local energy functions. The result suggests the hidden Yangian module structure on the \hatsl level $l$ integrable modules, which is consistent with the earlier work [1] in the level one case. Also we prove the fermionic character formula of the \hatsl level $l$ integrable representations in consequence.Comment: 27 pages, Plain Tex, epsf.tex, 7 figures; minor revision. identical with the version to be published in Commun.Math.Phy

Properties of Composite Electrodes for All-solid-state Fluoride-ion Secondary Batteries Processed by High-pressure Torsion

All-solid-state fluoride-ion batteries (FIBs) using metal/metal fluorides are expected to be the next generation of storage batteries because they exhibit high volumetric energy densities by utilizing multielectron reactions, compared to the current lithium-ion batteries. However, method of fabricating a composite electrode for all-solid-state fluoride-ion batteries has not yet been established. A fabrication method for a composite electrode that disperses the active material and solid electrolyte is required. To approach this problem, in this study, we employed a high-pressure torsion (HPT) method, in which an active material, solid electrolyte, and conductive agent can be mixed with size reduction, as a new process and prepared Cu (active material)/PbSnF₄ (solid electrolyte)/acetylene black (conductive agent) cathode composites. The crystalline sizes of Cu and PbSnF₄ were significantly reduced. The apparent grain boundary resistance was also reduced owing to the more homogeneous distribution in the cathode composites after HPT processing. These structural and morphological changes led to high electrochemical performances, compared to a cathode composite without HPT

Development of ground pipeline system for high-level scientific data products of the Hisaki satellite mission and its application to planetary space weather

The Hisaki satellite is the first-ever space telescope mission dedicated to planetary sciences. Atmospheres and magnetospheres of our solar system planets are continuously monitored by the extreme ultraviolet (EUV) spectrometer onboard Hisaki. This paper describes a data pipeline system developed for processing high-level scientific and ancillary data products from the Hisaki mission. The telemetry data downlinked from the satellite are stored in a ground telemetry database, processed in the pipeline to imaging spectral data with a 1-min temporal resolution and ancillary data products, and then archived in a public database. The imaging spectra can be further reduced to higher-level data products for practical scientific use. For example, light curves of the power emitted from Jupiter’s aurora and plasma torus with a temporal resolution of 10-min can be reduced from the imaging spectral data; the reduced light curves reveal the transport processes of energy and mass in Jupiter’s magnetosphere and associated interplanetary solar wind conditions. Continuous monitoring with Hisaki will contribute considerably to our understanding of space weather relating to planets in our solar system

Experimental inspection of a computationally-designed NiCrMnSi Heusler alloy with high Curie temperature

Nowadays advanced magnetic tunnel junction applications demand very high tunnel magnetoresistance at room temperature, thus it is quite important to explore high Curie temperature Tc half-metallic Heusler alloys. In this article rst-principles calculation unveiled that NiCrMnSi has Tc of 1200 K comparable to that of the traditional Co2MnSi Heusler alloys, even though it does not contain Co element. In addition, we examined whether NiCrMnSi Heulser phase lms can be obtained by a magnetron sputtering on MgO substrates. The results of the structural analysis and rst-principles calculations indicated that NiCrMnSi Heusler phase is metastable. A possible route to obtain metastable NiCrMnSi Heusler alloy is to utilize appropriate templates

Magnetic tunnel junctions with a B2-ordered CoFeCrAl equiatomic Heusler alloy

The equiatomic quaternary Heusler alloy CoFeCrAl is a candidate material for spin-gapless semiconductors (SGSs). However, to date, there have been no experimental attempts at fabricating a junction device. This paper reports a fully epitaxial (001)-oriented MgO barrier magnetic tunnel junction (MTJ) with CoFeCrAl electrodes grown on a Cr buffer. X-ray and electron diffraction measurements show that the (001) CoFeCrAl electrode films with atomically flat surfaces have a B2-ordered phase. The saturation magnetization is 380 emu/cm3, almost the same as the value given by the Slater–Pauling–like rule, and the maximum tunnel magnetoresistance ratios at 300 K and 10 K are 87% and 165%, respectively. Cross-sectional electron diffraction analysis shows that the MTJs have MgO interfaces with fewer dislocations. The temperature- and bias-voltage dependence of the transport measurements indicates magnon-induced inelastic electron tunneling overlapping with the coherent electron tunneling. X-ray magnetic circular dichroism (XMCD) measurements show a ferromagnetic arrangement of the Co and Fe magnetic moments of B2-ordered CoFeCrAl, in contrast to the ferrimagnetic arrangement predicted for the Y -ordered state possessing SGS characteristics. Ab-initio calculations taking account of the Cr-Fe swap disorder qualitatively explain the XMCD results. Finally, the effect of the Cr-Fe swap disorder on the ability for electronic states to allow coherent electron tunneling is discussed