Current-induced torques due to compensated antiferromagnets

We analyse the influence of current induced torques on the magnetization configuration of a ferromagnet in a circuit containing a compensated antiferromagnet. We argue that these torques are generically non-zero and support this conclusion with a microscopic NEGF calculation for a circuit containing antiferromagnetic NiMn and ferromagnetic Co layers. Because of symmetry dictated differences in the form of the current-induced torque, the phase diagram which expresses the dependence of ferromagnet configuration on current and external magnetic field differs qualitatively from its ferromagnet-only counterpart.Comment: 4 pages, 5 figure

Ab-initio GMR and current-induced torques in Au/Cr multilayers

We report on an {\em ab-initio} study of giant magnetoresistance (GMR) and current-induced-torques (CITs) in Cr/Au multilayers that is based on non-equilibrium Green's functions and spin density functional theory. We find substantial GMR due primarily to a spin-dependent resonance centered at the Cr/Au interface and predict that the CITs are strong enough to switch the antiferromagnetic order parameter at current-densities $\sim 100$ times smaller than typical ferromagnetic metal circuit switching densities.Comment: 8 pages, 6 figure

Magnetic dynamics with spin transfer torques near the Curie temperature

We use atomistic stochastic Landau-Lifshitz-Slonczewski simulations to study the interaction between large thermal fluctuations and spin transfer torques in the magnetic layers of spin valves. At temperatures near the Curie temperature $T_{\rm C}$, spin currents measurably change the size of the magnetization (i.e. there is a {\it longitudinal} spin transfer effect). The change in magnetization of the free magnetic layer in a spin valve modifies the temperature dependence of the applied field-applied current phase diagram for temperatures near $T_{\rm C}$. These atomistic simulations can be accurately described by a Landau-Lifshitz-Bloch + Slonczewski equation, which is a thermally averaged mean field theory. Both the simulation and the mean field theory show that a longitudinal spin transfer effect can be a substantial fraction of the magnetization close to $T_{\rm C}$.Comment: 8 pages, 6 figure

The quality of political information

The article conceptualizes the quality of political information and shows how the concept can be used for empirical research. I distinguish three aspects of quality (intelligibility, relevance, validity) and use them to judge the constituent foundations of political information, that is component claims (statements of alleged facts) and connection claims (argumentative statements created by causally linking two component claims). The resulting conceptual map thus entails six manifestations of information quality (component claimintelligibility, connection claim intelligibility, component claimrelevance, connection claim relevance, component claim validity, and connection claim validity). I explain how the conceptual map can be used to make sense of the eclectic variety of existing research, and how it can advance new empirical research, as a guide for determining variation in information quality, as a conceptual template for the analysis of different types of political messages and their common quality deficiencies, and as a generator of new research questions and theoretical expectations

Aquatic biosurvey of the Lovell River on UNH land

We assessed the physical, chemical and biological conditions at two sites along the Lovell River on University of New Hampshire (UNH) -owned conservation land. The discharge was 4.4 m3 s-1 at Site 1 and 5.7 m3 s -1 downstream at Site 2. Canopy coverage ranged from 8-25%. Canopy was dominated by Eastern Hemlock (79-84%). Much of the stream was strewn with large boulders and the substrate consisted of rocks of highly variable sizes ( 3-549 cm dia.). Specific conductivity (22.1-23.3 µS), pH (6.4) and temperature (7.9-8.3 °C) varied little between sites. Macro-invertebrate bio-indices indicated either excellent water quality with no apparent organic pollution (3.0/10) or good water quality with possible slight organic pollution (4.4/10)