M. Kofu

Weakly coupled $s = 1/2$ quantum spin singlets in Ba$_{3}$Cr$_{2}$O$_{8}$ (2008)

Kofu, M., Kim, J. H., Ji, S., Lee, S. H., Ueda, H., Qiu, Y., ...

Using single crystal inelastic neutron scattering with and without application of an external magnetic field and powder neutron diffraction, we have characterized magnetic interactions in...

Neutron scattering study of the oxypnictide superconductor La(O,F)FeAs (2008)

Qiu, Y., Kofu, M., Bao, Wei, Huang, Q., Yildirim, T., ...

The newly discovered superconductor La(O,F)FeAs (Tc = 26 K) was investigated using the neutron scattering technique. No spin-density-wave (SDW) order was observed in the normal state nor in the...

Hidden quantum spin gap state in the static stripe phase of La$_{2-x}$Sr$_{x}$CuO$_{4}$ (2008)

Kofu, M., Fujita, M., Eisaki, H., Yamada, K.

We have systematically studied the low-energy spin excitations in La_2-xSr_xCuO_4 by performing elastic and inelastic neutron scattering on single crystals with four different hole concentrations,...

Dispersion and energy spectrum of spin excitations in an underdoped La_1.90Sr_0.10CuO_4 (2007)

Kofu, M., Yokoo, T., Trouw, F., Yamada, K.

We performed inelastic neutron experiments on underdoped La_2-xSr_xCuO_4(x=0.10, T_c=28.6K) using a time-of-flight neutron scattering technique. Four incommensurate peaks on the two-dimensional...

Shadow bands in single-layered Bi_2Sr_2CuO_6 studied by angle-resolved photoemission spectroscopy (2006)

Nakayama, K., Sato, T., Dobashi, T., Terashima, K., Souma, S., Matsui, H., ...

We have performed systematic angle-resolved photoemission spectroscopy (ARPES) on single-layered cuprate superconductor Bi2Sr2CuO6 to elucidate the origin of shadow band. We found that the shadow...

Zn and Ni doping effects on the low-energy spin excitations in La$_{1.85}$Sr$_{0.15}$CuO$_{4}$ (2004)

Kofu, M., Kimura, H., Hirota, K.

Impurity effects of Zn and Ni on the low-energy spin excitations were systematically studied in optimally doped La1.85Sr0.15Cu1-yAyO4 (A=Zn, Ni) by neutron scattering. Impurity-free La1.85Sr0.15CuO4...

Novel in-gap spin state in Zn-doped La_1.85Sr_0.15CuO_4 (2002)

Kimura, H., Kofu, M., Matsumoto, Y., Hirota, K.

Low-energy spin excitations of La1.85Sr0.15Cu1-yZnyO4 were studied by neutron scattering. In y=0.004, the incommensurate magnetic peaks show a well defined ``spin gap'' below Tc. The magnetic signals...