How strategic alliances change : The case of Japanese semiconductor business

The structure of the semiconductor industry has been changing recently. Japanese companies have lost their competitiveness, while their US and Korean counterparts have been strenthening theirs. At the same time, the map of the inter-firm relationships in the IT industry is changing. Patterns of strategic alliances in the semiconductors business have been evolving and have become complicated. We will investigate the transformation of strategic alliances, and we will propose how Japanese semiconductor companies can recover through a new type of alliance

Inertia, diffusion and dynamics of a driven skyrmion

Skyrmions recently discovered in chiral magnets are a promising candidate for magnetic storage devices because of their topological stability, small size ($\sim 3-100$nm), and ultra-low threshold current density ($\sim 10^{6}$A/m$^2$) to drive their motion. However, the time-dependent dynamics has hitherto been largely unexplored. Here we show, by combining the numerical solution of the Landau-Lifshitz-Gilbert equation and the analysis of a generalized Thiele's equation, that inertial effects are almost completely absent in skyrmion dynamics driven by a time-dependent current. In contrast, the response to time-dependent magnetic forces and thermal fluctuations depends strongly on frequency and is described by a large effective mass and a (anti-) damping depending on the acceleration of the skyrmion. Thermal diffusion is strongly suppressed by the cyclotron motion and is proportional to the Gilbert damping coefficient $\alpha$. This indicates that the skyrmion position is stable, and its motion responds to the time-dependent current without delay or retardation even if it is fast. These findings demonstrate the advantages of skyrmions as information carriers.Comment: 9 pages, 10 figure