65 research outputs found
Electronic Structure and Electron Correlation in LaFeAsO_{1-x}F_x and LaFePO_{1-x}F_x
Photoemission spectroscopy is used to investigate the electronic structure of
the newly discovered iron-based superconductors LaFeAsO_{1-x}F_x and
LaFePO_{1-x}F_x. Line shapes of the Fe 2p core-level spectra suggest an
itinerant character of Fe 3d electrons. The valence-band spectra are generally
consistent with band-structure calculations except for the shifts of Fe
3d-derived peaks toward the Fermi level. From spectra taken in the Fe 3p -> 3d
core-absorption region, we have obtained the experimental Fe 3d partial density
of states, and explained it in terms of a band-structure calculation with a
phenomenological self-energy correction, yielding a mass renormalization factor
of ~< 2.Comment: 4 pages, 5 figure
Enhancement of perpendicular exchange bias by introducing twin boundary in Pt/Co/α-Cr₂O₃/α-V₂O₃ epitaxial film
Perpendicular exchange anisotropy at the Co/α-Cr₂O₃ interface was investigated using the two types of films: the film with the single crystalline α-Cr₂O₃ and that with the twinned a-Cr₂O₃. Exchange anisotropy energy density JK of the film with the single crystalline α-Cr₂O₃ was ~0.09 erg/cm² whereas JK of the film with the twinned α-Cr₂O₃ was ~0.43 erg/cm², more than 4-times enhancement. We discussed the mechanism of the enhancement of JK based on the exchange coupling at the twin boundary and that the spin frustration at the twin boundary can be the origin of the enhancement of JK.Y.Shiratsuchi, S.Yoshida, S.Onoue, et al. Enhancement of perpendicular exchange bias by introducing twin boundary in Pt/Co/a-Cr₂O₃/a-V₂O₃ epitaxial film. Materials Transactions 60, 2028 (2019); https://doi.org/10.2320/matertrans.MT-M2019102
Determination of specific ion positions of Cr³⁺ and O²- in Cr₂O₃ thin films and their relationship to exchange anisotropy at Co/Cr₂O₃ interfaces
The structures of antiferromagnetic Cr₂O₃(0001) thin films with perpendicular exchange bias were investigated using reflection high-energy electron diffraction, X-ray reflectivity, and synchrotron X-ray diffraction. We mainly investigated the specific ion positions of Cr³⁺ and O²- in the corundum structure and discussed their relationship to the magnetic anisotropy of Cr₂O₃. The Cr₂O₃(0001) thin film grown on a Pt(111) buffer layer exhibited a perpendicular exchange anisotropy density of 0.42 mJ/m², in which the Cr³⁺ position is the primary factor in the enhancement of magnetic anisotropy due to dipolar-interaction. In contrast, the single-crystalline Cr₂O₃(0001) film grown on a α-Al₂O₃(0001) substrate featured a low exchange magnetic anisotropy of 0.098 mJ/m². In this film, the Cr³⁺ position parameter is an insignificant factor, leading to low magnetic anisotropy. The O²- ion position also differs between the two types of films, which can affect both the magnetic anisotropy energy originating from fine structures and the magneto-electric properties of Cr₂O₃.Yu Shiratsuchi, Yuuta Nakano, Nobuhito Inami, Tetsuro Ueno, Kanta Ono, Reiji Kumai, Ryoko Sagayama, and Ryoichi Nakatani, Journal of Applied Physics 123, 103903 (2018); https://doi.org/10.1063/1.5020620
Comparison of Solid-Water Partitions of Radiocesium in River Waters in Fukushima and Chernobyl Areas
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