Masafumi Udagawa

Numerical Study of Current-Induced Domain-Wall Dynamics: Crossover from Spin Transfer to Momentum Transfer (2008)

Matsubayashi, Daisuke, Udagawa, Masafumi, Ogata, Masao

We study current-induced dynamics of a magnetic domain wall by solving a time-dependent Schr\"{o}dinger equation combined with Landau-Lifshitz-Gilbert equation in a one-dimensional electron system...

Charge ordering and coexistence of charge fluctuations in quasi-two-dimensional organic conductors $\theta$-(BEDT-TTF)$_2X$ (2007)

Udagawa, Masafumi, Motome, Yukitoshi

We present a scenario for the peculiar coexistence of charge fluctuations observed in quasi-2D 1/4-filled organic conductors $\theta$-(BEDT-TTF)$_2X$ in the quantum critical regime where the charge...

Formation of non-unitary state near the upper-critical field of Sr$_2$RuO$_4$ (2005)

Udagawa, Masafumi, Yanase, Youichi, Ogata, Masao

We have studied the superconducting state of Sr$_2$RuO$_4$ under a magnetic field parallel to the superconducting plane. We show that due to a weak spin-orbit coupling, non-unitary...

Effects of Fermi surface and superconducting gap structure in the field-rotational experiments: A possible explanation of the cusp-like singularity in YNi$_2$B$_2$C (2004)

Udagawa, Masafumi, Yanase, Youichi, Ogata, Masao

We have studied the field-orientational dependence of zero-energy density of states (FODOS) for a series of systems with different Fermi surface and superconducting gap structures. Instead of...

Influence of superconducting gap structure on the quasiparticle spectrum in the vortex state (2004)

Udagawa, Masafumi, Yanase, Youichi, Ogata, Masao

We study the vortex state of a layered superconductor with vertical line nodes on its Fermi surface when a magnetic field is applied in the ab-plane direction. We rotate the magnetic field within the...