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A highly spin-polarized electron beam is extracted via field emission from a ⟨100⟩-oriented Heusler alloy Co2MnGa emitter, which is fabricated through ion milling of a crystallized thin film and well characterized through H2-promoted field evaporation and field ion microscopy (FIM). Crystalline facets of low-index planes such as the (100) and {011} planes can be observed as ring structures in the H2-Ne FIM images, despite the ternary nature of the alloy. The well-defined (100) surface at the emitter apex is the emission site, having higher emission current than other locations. The maximum spin polarization of the field-emitted electrons from the Co2MnGa(100) surface is 61%–76% and can be observed under a 1-nA probe current at 44 K. Although decreased spin polarization is observed with elapsed time, cleaning performed by the field evaporation process restores the spin polarization to the initial value. The spin polarization of more than 60% obtained even at room temperature surpasses those previously reported for transition metals such as Fe, Co, and Cr on W tips. [ABSTRACT FROM AUTHOR]

An advanced ionizing radiation monitoring network (AIRMN) system using a single-crystal SrI2(Eu) scintillator has been developed. The SrI2(Eu)-scintillator (25 mmφ × 25 mm) has excellent material properties, including a high light yield (>80 000 photons/MeV), a high photoelectric cross section, and high energy resolution (<4%). The system has a multi-pixel photon counter as a light detector. The resolution and sensitivity of the new AIRMN allow the radioactive Cs originating from the Fukushima Daiichi Nuclear Power Plant accident to be distinguished from other radioactive species, leading to the precise assessment of the ambient dose originating from 134Cs and 137Cs radiation. Furthermore, a software platform is described that is adopted in the AIRMN and based on the use of the ANSI N42-42 Data File Format published by the National Institute of Standards and Technology. It allows for the standardization of ionizing radiation monitoring. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: We measured spin polarization of electrons field-emitted from half-metallic Co2MnSi thin film grown on a W(001) facet via chromium buffer layer using Mott scattering. For spontaneously magnetized samples, values of polarization at room temperature were observed in a range from 10% to 46% and the polarization direction was 〈110〉 orientation of substrate tungsten, which agreed with an easy axis of magnetization of bulky Co2MnSi. An enhancement of polarization was observed as a consequence of applying a magnetic field of 350G perpendicular to the emitter axis after the annealing at 800K. This result is considered to be caused by improvement in crystallinity of the evaporated film due to annealing. [Copyright &y& Elsevier]

Magnetite (Fe3O4) is oxidative resistant and has a half metallic property and is expected to have spintronic applications. In this work, <110>-oriented single crystal magnetite whiskers, 30–300 nm in diameter, were synthesized on a stainless steel plate by means of the combustion flame thermal oxidation process. An electron source with this single magnetite whisker was fabricated by using a microsampling instrument in a focused ion beam system. The spin polarization of the electron source was found to be 15% at room temperature by using a Mott electron polarimeter. [ABSTRACT FROM AUTHOR]

The authors investigated the Verwey transition in field-emitted electrons from a <110>-oriented magnetite whisker by means of temperature and emission-current-controlled spin-polarization measurements. Under a condition of total emission current of 1.5 nA, which is relatively high within the measured range, the spin polarization began to increase around 100 K due to the Verwey transition. At the low-temperature region, the spin polarization was sensitive to the emission current and the energy. Therefore, it is suggested that t2g band of Fe3O4 at the surface becomes narrower and possesses lower energy than that in an ideal bulky condition. [ABSTRACT FROM AUTHOR]