Disproportionation Transition at Critical Interaction Strength: Na1/2_{1/2}CoO2_2

Charge disproportionation (CD) and spin differentiation in Na$_{1/2}$CoO$_2$ are studied using the correlated band theory approach. The simultaneous CD and gap opening seen previously is followed through a first order charge disproportionation transition 2Co$^{3.5+} \to$ Co$^{3+}$+Co$^{4+}$, whose ionic identities are connected more closely to spin (S=0, S=1/2 respectively) than to real charge. Disproportionation in the Co $a_g$ orbital is compensated by opposing charge rearrangement in other 3d orbitals. At the transition large and opposing discontinuities in the (all-electron) kinetic and potential energies are slightly more than balanced by a gain in correlation energy. The CD state is compared to characteristics of the observed charge-ordered insulating phase in Na$_{1/2}$CoO$_2$, suggesting the Coulomb repulsion value $U$ is concentration-dependent, with $U(x=1/2)\simeq$3.5 eV.Comment: 4 pages and 4 embedded figure

Reorganizing through Lean Principles

In August 2014, the director of the Collections, Acquisitions, and Discovery division within the University of Nevada, Las Vegas (UNLV) Libraries announced that the division would be reorganized to best use the skills and strengths of existing staff. This division, responsible for acquiring, organizing, maintaining, and making discoverable all needed and relevant materials would be composed of three departments, and the Resource Acquisition, Sharing, and Digital Scholarship department (containing the Resource Acquisition and Sharing Unit) would be one of them. To fulfill the goals of the reorganization, the acquisitions team used Lean principles and tools, specifically the value stream map, to understand and improve its processes

The Importance of Being Lean: Using Lean Principles and Tools to Improve Acquisitions Workflows

This presentation demonstrated how the UNLV University Libraries Acquisitions team is using Lean principles to analyze and improve acquisitions processes for firm and approval print and electronic monographic workflows. Lean process improvement is a system of concepts and tools to help an organization provide high value and high quality to our users in an efficient manner. In this session, the presenters provided a brief overview of lean principles and how this system can be adapted to a library setting. The presenters showed working examples of Lean-specific tools, like a Value-Stream map, that helped improve the UNLV Libraries acquisitions process

Epilogue: The Need for a New and Critical Democracy

Democratic critiques of neoliberalism have been comparatively rare, and positive democratic rejoinders to the social and political ruins of neoliberalism have been rarer. The question thus presents itself – what would an overtly democratic critique of neoliberalism look like and, beyond critique, what would a constructive democratic response to neoliberalism entail

Of Rights and Regulation

This chapter explores the development of social provisioning as a matter not of right but of democratic administration in France and the United States in the nineteenth century. The authors take issue with conventional chronologies of rights development, which see civil and political rights being developed in the eighteenth and nineteenth centuries, with social rights appearing in the twentieth. Such categories and sequencing obscure the ways in which democratic administrations took the problem of social provisioning seriously. A history of socio-economic rights cannot be distinguished from the less formal technologies of socio-economic regulation that were an integral part of the democratic question across the nineteenth century, and, in particular, the modernisation of regulatory governance. The democratisation of administrative powers precluded any sharp distinction among the political, the social and the economic. For better and for worse, this process took place through the building, rescaling and redefining of older, pre-democratic technologies of governance in response to what were perceived as pressing public problems

Temperature dependence of the coercive field in single-domain particle systems

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on 29/04/200

Spin-dependent phenomena and device concepts explored in (Ga,Mn)As

Over the past two decades, the research of (Ga,Mn)As has led to a deeper understanding of relativistic spin-dependent phenomena in magnetic systems. It has also led to discoveries of new effects and demonstrations of unprecedented functionalities of experimental spintronic devices with general applicability to a wide range of materials. In this article we review the basic material properties that make (Ga,Mn)As a favorable test-bed system for spintronics research and discuss contributions of (Ga,Mn)As studies in the general context of the spin-dependent phenomena and device concepts. Special focus is on the spin-orbit coupling induced effects and the reviewed topics include the interaction of spin with electrical current, light, and heat.Comment: 47 pages, 41 figure

Influence of antisymmetric exchange interaction on quantum tunneling of magnetization in a dimeric molecular magnet Mn6

We present magnetization measurements on the single molecule magnet Mn6, revealing various tunnel transitions inconsistent with a giant-spin description. We propose a dimeric model of the molecule with two coupled spins S=6, which involves crystal-field anisotropy, symmetric Heisenberg exchange interaction, and antisymmetric Dzyaloshinskii-Moriya exchange interaction. We show that this simplified model of the molecule explains the experimentally observed tunnel transitions and that the antisymmetric exchange interaction between the spins gives rise to tunneling processes between spin states belonging to different spin multiplets.Comment: 5 pages, 4 figure