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Benchmark study of DFT with Eu and Np M$"o$ssbauer isomer shifts using second-order Douglas-Kroll-Hess Hamiltonian

金子 政志; 渡邉 雅之; 宮下 直*; 中島 覚*

Hyperfine Interactions, 239(1), p.20_1 - 20_10, 2018/12


fブロック化合物に対する密度汎関数計算の精度向上を目指し、$$^{151}$$Eu, $$^{237}$$Npメスバウアー異性体シフトを指標として、二次Douglas-Kroll-Hess(DKH2)ハミルトニアンを用いて相対論密度汎関数法のベンチマーク研究を行った。純粋な密度汎関数法による電子交換相互作用とHartree-Fockによる厳密な電子交換相互作用の混合パラメータを変えて、メスバウアー異性体シフトの実験値に対する平均二乗誤差を比較した。その結果、$$^{151}$$Eu, $$^{237}$$Npメスバウアー異性体シフトに対して、厳密な交換相互作用の割合が、それぞれ30, 60%のときに、平均二乗誤差が最小になることが明らかになった。


Estimation of $$Delta$$${it R}$/${it R}$ values by benchmark study of the M$"o$ssbauer Isomer shifts for Ru, Os complexes using relativistic DFT calculations

金子 政志; 安原 大樹*; 宮下 直*; 中島 覚*

Hyperfine Interactions, 238(1), p.36_1 - 36_9, 2017/11



Ru, Os錯体の結合状態に対する密度汎関数計算の妥当性を評価することを目的として、$$^{99}$$Ru, $$^{189}$$Osのメスバウアー異性体シフト実験値を用いて理論計算手法のベンチマークを行った。結果、Ru錯体およびOs錯体の原子核位置での電子密度の計算値はメスバウアー異性体シフト実験値とよく相関した。


Bonding study on trivalent europium complexes by combining M$"o$ssbauer isomer shifts with density functional calculations

金子 政志; 渡邉 雅之; 宮下 直*; 中島 覚*

Radioisotopes, 66(8), p.289 - 300, 2017/08




金子 政志

放射化学, (35), p.36 - 39, 2017/03



A Spin-crossover phenomenon depending on the environment around an iron atom for the assembled coordination polymers

中島 覚*; 金子 政志

Advances in Chemistry Research, Vol.36, p.171 - 195, 2017/01



$$^{61}$$Ni synchrotron radiation-based M$"o$ssbauer spectroscopy of nickel-based nanoparticles with hexagonal structure

増田 亮*; 小林 康浩*; 北尾 真司*; 黒葛 真行*; 齋藤 真器名*; 依田 芳卓*; 三井 隆也; 細井 浩平*; 小林 浩和*; 北川 宏*; et al.

Scientific Reports (Internet), 6, p.20861_1 - 20861_8, 2016/02

 被引用回数:5 パーセンタイル:50.18(Multidisciplinary Sciences)

We measured the SR M$"o$ssbauer spectra of Ni nanoparticles with a hexagonal structure that were synthesized by chemical reduction. To obtain M$"o$ssbauer spectra of the nanoparticles without 61-Ni enrichment, we developed a measurement system for $$^{61}$$Ni SR M$"o$ssbauer absorption spectroscopy without X-ray windows between the standard energy alloy and detector. The counting rate of the $$^{61}$$Ni nuclear resonant scattering in the system was enhanced by the detection of internal conversion electrons and the close proximity between the energy standard and the detector. The spectrum measured at 4 K revealed the internal magnetic field of the nanoparticles was 3.4 T, corresponding to a Ni atomic magnetic moment of 0.3 Bohr magneton. This differs from the value of Ni$$_{3}$$C and the theoretically predicted value of hexagonal closed packed Ni and suggested the nanoparticle possessed intermediate carbon content between hcp-Ni and Ni$$_{3}$$C of approximately 10 atomic percent of Ni.


Attempt to measure magnetic hyperfine fields in metallic thin wires under spin Hall conditions using synchrotron-radiation M$"o$ssbauer spectroscopy

壬生 攻*; 三井 隆也; 田中 雅章*; 増田 亮*; 北尾 真司*; 小林 康浩*; 依田 芳卓*; 瀬戸 誠*

Journal of Applied Physics, 117(17), p.17E126_1 - 17E126_4, 2015/05

 被引用回数:2 パーセンタイル:82.81(Physics, Applied)

Measurement of the magnetic hyperfine fields in metallic thin wires under spin Hall conditions was attempted using the emerging technique synchrotron radiation M$"o$ssbauer spectroscopy. A M$"o$ssbauer probe layer of $$^{57}$$Fe(0.2 nm), $$^{57}$$Fe(0.6 nm), or $$^{119}$$Sn(0.6 nm) was embedded as an electron spin detector near the surfaces of V, Au, Pt, and $$^{56}$$Fe wires. The magnitudes of the magnetic hyperfine fields at the $$^{57}$$Fe and $$^{119}$$Sn nuclear sites that could be enhanced by nonequilibrium conduction electron spin polarization were measured both without and with the application of an electric current along the wire. Changes in the M$"o$ssbauer spectra were not clearly observed, indicating that the magnetic hyperfine field induced by nonequilibrium spin polarization is smaller than the detection limit at least for the measured systems and conditions.


$$^{57}$$Fe polarization dependent synchrotron M$"o$ssbauer spectroscopy using a diamond phase plate and an iron borate nuclear Bragg monochromator

三井 隆也; 今井 康彦*; 増田 亮*; 瀬戸 誠*; 壬生 攻*

Journal of Synchrotron Radiation, 22(2), p.427 - 435, 2015/03

 被引用回数:3 パーセンタイル:68.08(Instruments & Instrumentation)

Energy domain $$^{57}$$Fe polarization dependent synchrotron radiation M$"o$ssbauer spectroscopy was developed by using a diamond X-ray phase plate and an iron borate nuclear Bragg monochromator. The former controls the polarization of the incident synchrotron radiation X-rays and the latter filters the $$^{57}$$Fe M$"o$ssbauer radiation with a narrow bandwidth of 15 neV from the broadband synchrotron radiation. The developed nuclear diffraction optics allowed $$^{57}$$Fe M$"o$ssbauer studies to beperformed with various polarization states. In this paper, the spectrometer system, beam characterization, performance test experiments and a grazing incidence M$"o$ssbauer measurement of an isotope enriched iron thin film are described.


High-pressure radiative conductivity of dense silicate glasses with potential implications for dark magmas

村上 元彦*; Goncharov, A. F.*; 平尾 直久*; 増田 亮*; 三井 隆也; Thomas, S. M.*; Bina, C. R.*

Nature Communications (Internet), 5, p.5428_1 - 5428_6, 2014/11

 被引用回数:9 パーセンタイル:50.18(Multidisciplinary Sciences)

The possible presence of dense magmas at Earth's core mantle boundary is expected to substantially affect the dynamics and thermal evolution of Earth's interior. However, the thermal transport properties of silicate melts under relevant high-pressure conditions are poorly understood. Here we report in situ high pressure optical absorption and synchrotron M$"o$ssbauer spectroscopic measurements of iron enriched dense silicate glasses, as laboratory analogues for dense magmas, up to pressures of 85 GPa. Our results reveal a significant increase in absorption coefficients, by almost one order of magnitude with increasing pressure to $$sim$$50 GPa, most likely owing to gradual changes in electronic structure. This suggests that the radiative thermal conductivity of dense silicate melts may decrease with pressure and so may be significantly smaller than previously expected under core-mantle boundary conditions. Such dark magmas heterogeneously distributed in the lower mantle would result in significant lateral heterogeneity of heat flux through the core mantle boundary.


Development of $$^{125}$$Te synchrotron-radiation-based M$"o$ssbauer spectroscopy

黒葛 真行*; 北尾 真司*; 小林 康浩*; 齋藤 真器名*; 増田 亮*; 三井 隆也; 依田 芳卓*; 瀬戸 誠*

Hyperfine Interactions, 226(1), p.687 - 691, 2014/04

 被引用回数:2 パーセンタイル:30.92

The M$"o$ssbauer spectra of the 35.49 keV excited state of $$^{125}$$Te were observed in the energy domain using synchrotron radiation for the first time. The obtained isomer shifts and Debye temperature agree with previous experiments. These results show that this method will be applicable to various compounds.


$$^{125}$$Te synchrotron-radiation-based M$"o$ssbauer spectroscopy of Fe$$_{1.1}$$Te and FeTe$$_{0.5}$$Se

黒葛 真行*; 北尾 真司*; 小林 康浩*; 齋藤 真器名*; 増田 亮*; 三井 隆也; 依田 芳卓*; 瀬戸 誠*

Journal of the Physical Society of Japan, 83(4), p.044708_1 - 044708_4, 2014/04

 パーセンタイル:100(Physics, Multidisciplinary)

The $$^{125}$$Te M$"o$ssbauer spectra of Fe$$_{1.1}$$Te and FeTe$$_{0.5}$$Se$$_{0.5}$$ were measured using synchrotron-radiation-based M$"o$ssbauer spectroscopy. The hyper fine field of Te in the antiferromagnetic phase of Fe$$_{1.1}$$Te was evaluated to be 4(1) T at 20 K, and this hyper fine field is considered to be due to the transferred hyper fine field from Fe magnetic moments. The evaluated hyper fine field was comparatively large, suggesting the strong correlation with the magnetic moment of Fe that forms double stripe type magnetic structure. For the superconductor FeTe$$_{0.5}$$Se$$_{0.5}$$, no marked change in its M$"o$ssbauer parameters was observed below or above the superconducting transition temperature, indicating that the change in the electronic state of Te was small.


Synchrotron radiation-based M$"o$ssbauer spectra of $$^{174}$$Yb measured with internal conversion electrons

増田 亮*; 小林 康浩*; 北尾 真司*; 黒葛 真行*; 齋藤 真器名*; 依田 芳卓*; 三井 隆也; 伊賀 文俊*; 瀬戸 誠

Applied Physics Letters, 104(8), p.082411_1 - 082411_5, 2014/02

 被引用回数:9 パーセンタイル:45.24(Physics, Applied)




佐伯 正克

日本結晶学会誌, 46(6), p.415 - 420, 2004/12




佐伯 正克

JAERI-Review 2004-011, 54 Pages, 2004/03




$$^{238}$$U and $$^{57}$$Fe M$"o$ssbauer spectroscopic study of UFe$$_{2}$$

筒井 智嗣; 中田 正美; 小林 康浩*; 那須 三郎*; 芳賀 芳範; 大貫 惇睦

Hyperfine Interactions, 133(1-4), p.17 - 21, 2001/11



$$^{238}$$U M$"o$ssbauer study of UPt$$_{3}$$

筒井 智嗣; 中田 正美; 那須 三郎*; 芳賀 芳範; 山本 悦嗣; 木村 憲彰*; 大貫 惇睦

Journal of Magnetism and Magnetic Materials, 226-230(Part.1), p.87 - 88, 2001/05



$$^{238}$$U M$"o$ssbauer spectroscopic study of UX$$_{2}$$(X=Ga, P, As, Sb)

筒井 智嗣; 中田 正美; 那須 三郎*; 芳賀 芳範; 本間 徹生; 山本 悦嗣; 常盤 欣文; 青木 大*; Wi$'s$niewski, P.*; 大貫 惇睦

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.34 - 36, 2001/05

UX$$_{2}$$(X=Ga, P, As, Sb, Bi)はいずれも2次元原子配列を持つ磁性体であり、UGa$$_{2}$$は強磁性体、そのほかの化合物は反強磁性体である。de Haas-van Alphen効果測定によりUGa$$_{2}$$のフェルミ面は3次元フェルミ面だけで構成されているのに対し、その他の化合物のフェルミ面は2次元フェルミ面で構成されている。そこで本研究では、これらの化合物の原子配列、フェルミ面と5f軌道との相関を調べることを目的として$$^{238}$$Uメスバウアー分光測定を行った。これらの化合物ではすべて磁気秩序状態で電気四極子相互作用と磁気双極子相互作用が観測された。いずれの化合物も核位置の電場勾配の主軸と磁気モーメントの方向は平行である。電場勾配の符号は、UGa$$_{2}$$が正,ほかの化合物が負である。これらの結果は、これらの化合物においてフェルミ面の次元性が原子配列でなく、5f軌道や磁気構造と相関があることを示唆している。


$$^{238}$$U M$"o$ssbauer study on the magnetic properties of uranium-based heavy fermion superconductors

筒井 智嗣; 中田 正美; 那須 三郎*; 芳賀 芳範; 本間 徹生; 山本 悦嗣; 大國 仁*; 大貫 惇睦

Hyperfine Interactions, 126(1-4), p.335 - 340, 2000/07

 被引用回数:6 パーセンタイル:59.38(Physics, Atomic, Molecular & Chemical)



$$^{57}$$Fe M$"o$ssbauer spectroscopic study of U$$_{6}$$Fe

筒井 智嗣; 小林 康浩*; 中田 正美; 那須 三郎*; 山本 悦嗣; 芳賀 芳範; 大貫 惇睦

Journal of the Physical Society of Japan, 69(6), p.1764 - 1768, 2000/06

 被引用回数:2 パーセンタイル:82.43(Physics, Multidisciplinary)



Experimental study of the influence of magnetic phase transition on the M$"o$ssbauer time spectra of the nuclear forward scattering

三井 隆也; 北尾 真司*; 瀬戸 誠*; 依田 芳卓*; 菊田 惺志*

Journal of the Physical Society of Japan, 68(12), p.4049 - 4050, 1999/12

 被引用回数:1 パーセンタイル:81.34(Physics, Multidisciplinary)


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