Prediction of Giant Spin Motive Force due to Rashba Spin-Orbit Coupling

Magnetization dynamics in a ferromagnet can induce a spin-dependent electric field through spin motive force. Spin current generated by the spin-dependent electric field can in turn modify the magnetization dynamics through spin-transfer torque. While this feedback effect is usually weak and thus ignored, we predict that in Rashba spin-orbit coupling systems with large Rashba parameter $\alpha_{\rm R}$, the coupling generates the spin-dependent electric field [\pm(\alpha_{\rm R}m_e/e\hbar) (\vhat{z}\times \partial \vec{m}/\partial t)], which can be large enough to modify the magnetization dynamics significantly. This effect should be relevant for device applications based on ultrathin magnetic layers with strong Rashba spin-orbit coupling.Comment: 4+ pages, 2 figure

RISK-SHARING AS A LONG-TERM MOTIVATION TO FRANCHISE: ROLE OF FRANCHISING EXPERIENCE

This study aimed to examine a long-term motivation for franchising by considering the influence of experience franchisors gain through conducting the franchising strategy. The study mainly investigates the moderating effect of franchising experience on the relationship between three main motivations for franchising (derived from agency theory, resource scarcity theory, and risk-sharing theory) and firms’ degree of franchising in the restaurant context. Dynamic panel data model was employed and the findings suggest that not only do restaurant companies’ franchising experience positively affect firms’ degree of franchising, but also that those experiences positively moderate the relationship between risk sharing motivation and the degree of franchising. The findings lead to theoretical and practical implications and suggestions for future research

Collapse or Swelling Dynamics of Homopolymer Rings: Self-consistent Hartree approach

We investigate by the use of the Martin - Siggia - Rose generating functional technique and the self - consistent Hartree approximation, the dynamics of the ring homopolymer collapse (swelling) following an instantaneous change into a poor (good) solvent conditions.The equation of motion for the time dependent monomer - to - monomer correlation function is systematically derived. It is argued that for describing of the coarse - graining process (which neglects the capillary instability and the coalescence of ``pearls'') the Rouse mode representation is very helpful, so that the resulting equations of motion can be simply solved numerically. In the case of the collapse this solution is analyzed in the framework of the hierarchically crumpled fractal picture, with crumples of successively growing scale along the chain. The presented numerical results are in line with the corresponding simple scaling argumentation which in particular shows that the characteristic collapse time of a segment of length $g$ scales as $t^* \sim \zeta_0 g/\tau$ (where $\zeta_0$ is a bare friction coefficient and $\tau$ is a depth of quench). In contrast to the collapse the globule swelling can be seen (in the case that topological effects are neglected) as a homogeneous expansion of the globule interior. The swelling of each Rouse mode as well as gyration radius $R_g$ is discussed.Comment: 20 pages, 7 figures, submitted to Phys. Rev.

Chiral magnetoresistance in Pt/Co/Pt zigzag wires

The Rashba effect leads to a chiral precession of the spins of moving electrons while the Dzyaloshinskii-Moriya interaction (DMI) generates preference towards a chiral profile of local spins. We predict that the exchange interaction between these two spin systems results in a 'chiral' magnetoresistance depending on the chirality of the local spin texture. We observe this magnetoresistance by measuring the domain wall (DW) resistance in a uniquely designed Pt/Co/Pt zigzag wire, and by changing the chirality of the DW with applying an in-plane magnetic field. A chirality-dependent DW resistance is found, and a quantitative analysis shows a good agreement with a theory based on the Rashba model. Moreover, the DW resistance measurement allows us to independently determine the strength of the Rashba effect and the DMI simultaneously, and the result implies a possible correlation between the Rashba effect, the DMI, and the symmetric Heisenberg exchange

Void and beyond : reading between the void structures

Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2002.Includes bibliographical references (p. 66-68).At present, most cities confront similar issues that result from mass production, individualism, automobile-dependency and the advancement of democratic ownership. These issues have pushed our cities in a somewhat undesirable direction. Self-addressing buildings are everywhere disguised in a distorted framework of aesthetic knowledge. They are uncommunicative both to nature and their surroundings. This is the predominant feature of current cities. Considering the aforementioned issues, this thesis proposes a building that defines an edge of architecture by the various void structures it faces. Unlike the design method based on a particular program and solid dimensions of an object, it focuses primarily on the outer forces of the site, which is called 'void structures' . Void structures can be divided into three categories: Void structure in nature, void structure in human settlement, and the movement pattern of people. These undefined formal relationships between the void structures - the void created by the topography, human settlement, movement pattern of people and architectural elements - are the major consideration in defining architectural configuration. By relating these voids, physical and psychological boundaries are eliminated, and the architecture becomes the connector between nature and people. Architectural investigation of this thesis is divided into four elements: First, the earth is perfected by seeking a proper foundation. Second, formation of water body is sought as a means of connection to a natural void. Third , the roof is manipulated to turn an ecological void into a spatial void to produce aesthetic pleasure. Fourth, openings are studied to strengthen the relationship between void structures.by Kyung-A Lee.M.Arch

J/psi hadron interaction in vacuum and in QGP

Motivated by the recent lattice data that $J/\psi$ will survive up to 1.6$T_c$, we calculate the thermal width of $J/\psi$ at finite temperature in perturbative QCD. The inputs of the calculation are the parton quarkonium dissociation cross sections at the NLO in QCD, which were previously obtained by Song and Lee, and a gaussian charmonium wave function, whose size were fitted to an estimate by Wong by solving the schrodinger equation for charmonium in a potential extracted from the lattice at finite temperature. We find that the total thermal width above 1.4$T_c$ becomes larger than 100 to 200 MeV, depending on the effective thermal masses of the quark and gluon, which we take it to vary from 600 to 400 MeV.Comment: 4 pages, Talk at Quark Matter 200