Masayasu Takeda

Spiral spin structures and origin of the magnetoelectric coupling in YMn2O5

By combining neutron four-circle diffraction and polarized neutron-diffraction techniques we have determined the complex spin structures of a multiferroic

Dynamical Magnetic Structure of the Spin Density Wave State in Cr

{\text{YMn}}_{2}{\text{O}}_{5}

First Evidence of Interfacial Magnetic Roughness in Fe/Cr Artificial Multilayer Studied by Neutron Diffraction Measurement

that exhibits two ferroelectric phases at low temperatures. The obtained magnetic structure has spiral components in both the low-temperature ferroelectric phases that are magnetically commensurate and incommensurate, respectively. Among proposed microscopic theories for the magnetoelectric coupling, our results are consistent with both the spin-current mechanism and the magnetostriction mechanism. Our results also explain why the electric polarization changes at the low-temperature commensurate-to-incommensurate phase transition.

Orbital Ordering in Ferromagnetic Lu2V2O7

Inelastic neutron scattering experiments were carried out on the spin density wave (SDW) state of a single- Q chromium crystal. We made systematic investigations in a wide energy range up to ω∼100 meV by combining the triple axis and time-of-flight neutron spectroscopy. The q profile of the inelastic scattering is of a three-peaked structure; the commensurate scattering (CMS) at the antiferromagnetic superlattice and the incommensurate scattering (ICMS) near the wave vector points of the static SDW. In the longitudinal SDW state the dynamical susceptibility for the CMS increases with increasing ω and eventually overwhelms that for the ICMS. The ICMS, on the other hand, reaches a maximum at ω∼20 meV. This cross-over phenomenon is reflected in the temperature dependence of the magnetic excitations so that the CMS dominates at temperatures above 200 K.

Incommensurate Spin Correlations Induced by Magnetic Fe ions Substituted into Overdoped Bi1.75Pb0.35Sr1.90CuO6+z

We have investigated Fe/Cr artificial multilayers to elucidate the origin of a giant magnetoresistance effect (GMR), by neutron scattering measurement in external magnetic fields up to 0.8 Tesla. Intense diffuse scattering appears around the superlattice reflection corresponding to the antiferromagnetic Fe layer stacking. The magnetic diffuse scattering intensity decreases drastically in magnetic fields, which strongly suggests that the GMR effect in this system is dominated by the appearance of magnetic disorder at the interface between the Fe and the Cr layers.

Spin Density Wave in Epitaxial Cr(001)/Sn and Cr(001)/Au Multilayers with Nonmagnetic Spacer Layers

We have observed the orbital ordering in the ferromagnetic Mott-insulator Lu 2 V 2 O 7 by the polarized neutron diffraction technique. The orbital ordering pattern determined from the observed magnetic form factors can be explained in terms of a linear combination of wave functions | y z >, | z x > and | x y >;

Optical Investigation of Soliton in the One-Dimensional Ising-Like Antiferromagnet CsCoCl3

Spin correlations in the overdoped region of

Development and demonstration of in-situ SEOP 3He spin filter system for neutron spin analyzer on the SHARAKU polarized neutron reflectometer at J-PARC

{\text{Bi}}_{1.75}{\text{Pb}}_{0.35}{\text{Sr}}_{1.90}{\text{CuO}}_{6+z}

Role of magnetic chirality in polarization flip upon a commensurate-incommensurate magnetic phase transition in YMn2O5

have been explored with Fe-doped single crystals characterized by neutron scattering, muon-spin-rotation spectroscopy, and magnetic-susceptibility measurements. Static incommensurate spin correlations induced by the Fe spins are revealed by elastic neutron scattering. The resultant incommensurability

New electronic excitation at the boundary of ferromagnetic and antiferromagnetic phases in the one-dimensional Ising antiferromagnet CsFeCl3•2H2O

\ensuremath{\delta}