The Intrinsic Magnetization of Antiferromagnetic Textures

Antiferromagnets (AFMs) exhibit intrinsic magnetization when the order parameter spatially varies. This intrinsic spin is present even at equilibrium and can be interpreted as a twisting of the homogeneous AFM into a state with a finite spin. Because magnetic moments couple directly to external magnetic fields, the intrinsic magnetization can alter the dynamics of antiferromagnetic textures under such influence. Starting from the discrete Heisenberg model, we derive the continuum limit of the free energy of AFMs in the exchange approximation and explicitly rederive that the spatial variation of the antiferromagnetic order parameter is associated with an intrinsic magnetization density. We calculate the magnetization profile of a domain wall and discuss how the intrinsic magnetization reacts to external forces. We show conclusively, both analytically and numerically, that a spatially inhomogeneous magnetic field can move and control the position of domain walls in AFMs. By comparing our model to a commonly used alternative parametrization procedure for the continuum fields, we show that the physical interpretations of these fields depend critically on the choice of parametrization procedure for the discrete-to-continuous transition. This can explain why a significant amount of recent studies of the dynamics of AFMs, including effective models that describe the motion of antiferromagnetic domain walls, have neglected the intrinsic spin of the textured order parameter.Comment: 12 pages, 7 figure

The Patenting Behavior of Academic Founders

This study explores why academic entrepreneurs patent their inventions before and after creating a firm. Drawing on start-up data combined with patent data, we specifically examine the impact of five, relatively under-researched factors (scientific field, pace of technological development, technological uncertainty, entrepreneurial orientation, and patent effectiveness. The study shows that some scientific fields, technological uncertainty, and patent effectiveness are positively related to patent propensity, both before and after founding. The effects of pace of technological development and entrepreneurial orientation were timespecific. Our study suggests that patenting by academic entrepreneurs is driven by special rationales and that prior research on full-time scientists and established firms does not necessarily generalize to them. We discuss the implications of our findings both in terms of contribution to the current literature and technology transfer policies. --academic patenting

Spin-transport in multi-terminal normal metal - ferromagnet systems with non-collinear magnetizations

A theory of spin-transport in hybrid normal metal - ferromagnetic electronic circuits is developed, taking into account non-collinear spin-accumulation. Spin-transport through resistive elements is described by 4 conductance parameters. Microscopic expression for these conductances are derived in terms of scattering matrices and explicitly calculated for simple models. The circuit theory is applied to 2-terminal and 3-terminal devices attached to ferromagnetic reservoirs.Comment: 12 pages, 6 figures, to appear in Eur. Phys. J.

Measurement of Diffusion Coefficients of Dopants in Ge and Si Melts

No abstract availabl

Staggered Dynamics in Antiferromagnets by Collective Coordinates

Antiferromagnets can be used to store and manipulate spin information, but the coupled dynamics of the staggered field and the magnetization are very complex. We present a theory which is conceptually much simpler and which uses collective coordinates to describe staggered field dynamics in antiferromagnetic textures. The theory includes effects from dissipation, external magnetic fields, as well as reactive and dissipative current-induced torques. We conclude that, at low frequencies and amplitudes, currents induce collective motion by means of dissipative rather than reactive torques. The dynamics of a one-dimensional domain wall, pinned at 90$^{\circ}$ at its ends, are described as a driven harmonic oscillator with a natural frequency inversely proportional to the length of the texture.Comment: 4 pages, 2 figure

ACCOUNTING FOR SUSTAINABILITY: WHAT NEXT? A RESEARCH AGENDA

This working paper responds to increasing calls for more and different forms of accounting research involvement in accounting for sustainability. It seeks to provide background, clarify the accounting research issues, and suggest research methods. The background analysis indicates that accounting for sustainability must go beyond supplemental reporting of ecological and social information to include such emerging issues as integrated reporting of sustainability information along with financial reporting. Additional emerging issues are needs of users of sustainability reports, auditing and other assurance of sustainability information, and sustainability implications of financial failure, accounting and auditing failures, and lack of enforcement. Analysis of integrated reporting against traditional financial accounting theory concepts of the purpose of financial reporting and the postulates of going concern, reporting entity, monetary unit, and time period, indicates a need for substantial changes in the traditional financial accounting model if sustainability issues are to be integrated. The agenda concludes with five research issues and methods: - An accounting research framework for sustainability using general systems theory approaches that have been useful for similar emerging issues. - Reporting of sustainability information which has been the focus of most research to date, and the emerging important topic of integrated reporting. - Users of sustainable information, their uses and perceived needs, an area that has been largely neglected in research to date.- Auditing and assurance issues that are taking on greater importance as more users demand assurance for sustainability information. Issues include standards to be used and users expectations and reactions. - Financial distress and sustainability consequences of accounting and enforcement failures that are just now being recognized as sustainability issues.accounting for sustainability, integrated reporting, needs of users, audit, assurance