The University of Tokyo · 물리·천문학
히데타로 아베 교수의 연구실은 주로 전자스핀 공명 및 NMR을 활용한 이종 이온 및 고체 결정 내 불순물 이온의 스핀 동역학을 연구하며, 특히 구리 이온을 중심으로 한 다이머 구조와 스핀 상호작용의 기초 물리적 메커니즘을 규명하고자 한다. 다양한 배위 환경을 가진 구리(II) 복합체와 마그네슘 이소모르프 화합물의 자기적 성질을 단결정을 이용해 분석함으로써, 스핀-오르빗 결합, 스핀-스핀 상호작용, 그리고 비등방성 자기적 성질의 기원을 탐구한다. 이는 고체물리학과 분광학의 융합적 접근을 통해 새로운 자기적 현상의 기초 이론을 발전시키는 데 초점이 맞춰져 있다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
The paramagnetic resonance spectra of some ammine, ethylenediammine, and pyridine derivatives of hydrated cupric salts were examined, using their single crystals and microwaves of λ=32∼5 mm. In the cases of [Cu(NH 3 ) 4 ] SO 4 ·H 2 O and [Cu(en) 2 ] Cl 2 · x H 2 O, detailed analysis of spectra was performed using the structural data from x-ray analysis given by Mazzi. In the other cases, analysis was discussed under an assumption of inequivalent magnetic units. Results thus obtained are fully ex
Abstract The Cherenkov Telescope Array (CTA) is a next-generation ground-based observatory for gamma-ray astronomy at very high energies. The Large-Sized Telescope prototype (LST-1) is located at the CTA-North site, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to ≃20 GeV. LST-1 started performing astronomical observations in 2019 November, during its commissioning phase, and it has been taking data
At four microwave frequency bands (λ=78, 10, 16 and 32 mm), single crystals of copper acetate monohydrate, Cu(CH 3 COO) 2 H 2 O, were examined at room temperature by the method of paramagnetic resonance absorption, the results differing somewhat from those of usual copper salts. They can be explained by a spin-Hamiltonian with an effective spin S =1 which is considered to be originated from a pair of Cu ++ ions each in 2 D state, holding a strong interaction between them. This is consistent with
Single crystals of K 2 CuCl 4 ·2H 2 O and (NH 4 ) 2 CuCl 4 ·2H 2 O were examined at 7 different frequencies of microwaves (from 5.4 mm to 6.2 cm wave-lengths). If there were no exchange coupling, two absorption peaks would be expected corresponding to different g -values of two dissimilar Cu ++ ions in unit cell. Experimentally, however, only one peak can be observed at, longer wave-lengths, though the line width remarkably increases with decreasing wavelengths. At the wave-length of 5.4 mm two
Proton NMR in single crystals of Mn(HCOO) 2 ·2H 2 O has been observed at the temperature region from 2.5°K to 300°K. The shift of the resonance lines is explained by a dipole sum carried out by the use of atomic parameters presumed from those of the isomorphous magnesium formate. The results give a good agreement with the experimental data obtained above 4.2°K, if the magnetic moments of two kinds of manganese ions in the crystal are assumed to be \(c_{i}H/(T+\varTheta)\) for those of the one ki
Context. Certain types of supernova remnants (SNRs) in our Galaxy are assumed to be PeVatrons, capable of accelerating cosmic rays (CRs) to ~ PeV energies. However, conclusive observational evidence for this has not yet been found. The SNR G106.3+2.7, detected at 1–100 TeV energies by different γ-ray facilities, is one of the most promising PeVatron candidates. This SNR has a cometary shape, which can be divided into a head and a tail region with different physical conditions. However, in which
Abstract We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and ver
Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic teles
ABSTRACT Gamma-ray bursts (GRBs) are explosive transient events occurring at cosmological distances, releasing a large amount of energy as electromagnetic radiation over several energy bands. We report the detection of the long GRB 201216C by the MAGIC telescopes. The source is located at z = 1.1 and thus it is the farthest one detected at very high energies. The emission above 70 GeV of GRB 201216C is modelled together with multiwavelength data within a synchrotron and synchrotron self-Compton
Paramagnetic resonance absorption was investigated at centimeter wavelength region in single crystals of copper propionate monohydrate Cu(CH 3 CH 2 COO) 2 ·H 2 O. The spectrum obtained is not a normal one expected for a 2 D state of Cu ++ ions in crystals but similar to that observed in copper acetate monohydrate Cu(CH 3 COO) 2 ·H 2 O and more complicated. This spectrum can be explained by an effective spin Hamiltonian with an equivalent spin value S =1. This may lead us to a conclusion that eac
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