We studied single crystals of orthorhombic Sr2VO4 containing spin-singlet dimers of V4+(3d1) and those with Ti or Nb substituted for V. We found that both Ti and Nb dopings induce the evolution of a ...Curie-Weiss component in the magnetic susceptibility, but the rate of evolution with doping is several times higher for Nb doping. We also found that Nb doping induces the conduction of d electrons. These results can be explained by the hybridization of the Nb 4d states with the 3d states of the neighboring V ions, possibly causing rearrangement of the d electron in the doubly degenerate e states in the V ion.
The J-PARC neutrino facility will produce a very intense neutrino beam. The neutrinos can be detected at Korea as well as at Kamioka. We explore a possibility of two identical detectors at Kamioka ...and Korea exposed to the same neutrino beam. We show that this setup can be a promising experiment to measure the yet unknown neutrino parameters.
Ba0.9Sr0.1V13O18 exhibits two ordered phases caused by the charge/orbital ordering of the d electrons on the V ions. We have succeeded in observing photoinduced phase transitions over three phases in ...this compound: a transition from the low-temperature phase to the high-temperature phase within 0.3 ps, followed by a transition to the intermediate-temperature phase within 2 ps. The relationship between the symmetry at each of the three phases plays a key role in the dynamics of the photoinduced phase transitions in such a compound.
We studied the physical properties of Ba1−xSrxV13O18 single crystals, which exhibit three different phases caused by the orbital and charge degrees of freedom in V t2g states. We found from the ...magnetic susceptibility and the NMR measurement that the low-temperature phase of this series of compounds is characterized by the spin-singlet state. We also found from the electrical resistivity and optical conductivity spectra that these compounds become heavily anisotropic in the low-temperature phase with V trimerization, indicating that the orbital ordering of V t2g states causes the anisotropy of the electronic structure of this series of compounds.
The Kamiokande experiment was originally conceived and designed for the detection of proton decay signals. In the early stage of the experiment, it was decided to upgrade the detector so that ...astrophysical neutrinos including solar neutrinos in the 10 MeV energy range can be detected. When the upgrade of the detector was almost completed, a neutrino burst from Supernova SN1987A was detected. 2 years later, solar neutrinos were also observed with the energy, the directional and the arrival time information. This article describes the story of the Kamiokande experiment, and the subsequent development of the neutrino physics, including the neutrino oscillation, and astrophysics with Kamiokande and its successors; Super-Kamiokande and KamLAND.
In this talk I will present the status of the fabrication of prototype sapphire suspensions system for the KAGRA detector in Japan. I will also discuss the results of ongoing materials study at ...cryogenic temperature for the development cryogenic payload system for KAGRA.
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