Yukio Yasui

TL;DR: In this paper, the spin susceptibility and spin-lattice relaxation rate of 51 V nuclear moments of CaV 4 O 9 with tetragonal structure have been measured and the first example of quasi-two-dimensional spin systems with spin gap was provided.

TL;DR: Evidence of a Higgs transition from a magnetic Coulomb liquid to a ferromagnet in single-crystal Yb2Ti2O7 is reported, which is explained on the basis of a quantum spin-ice model, whose high-temperature phase is effectively described as a magnetism liquid, whereas the ground state shows a nearly collinear ferromaggnetism with gapped spin excitations.

TL;DR: In this article, a ferroelectric transition occurring simultaneously with a helical spin order has been found in both the polycrystalline and single-crystal samples of LiCuVO 4.

TL;DR: In this paper, a new structural transition has been found in Li 2 RuO 3 with a honeycomb lattice of edge-sharing RuO 6 octahedra, and a significant reduction of the bond lengths is found between two of the six Ru-Ru pairs of the hexagon in the low-temperature phase.

TL;DR: In this paper, the magnetic properties of Tb2Ti2O7 were investigated by means of neutron scattering on a single crystal of the rare earth ion and the results showed that the magnetic moments at the R sites are frustrated, if their nearest neighbor interaction is antiferromagnetic.