Search results for "ORIENTATION"
showing 10 items of 1041 documents
Investigation of the orientation of galaxies in clusters: the importance, methods and results of research
2018
Various models of structure formation can account for various aspects of the galaxy formation process on different scales, as well as for various observational features of structures. Thus, the investigation of galaxies orientation constitute a standard test of galaxies formation scenarios since observed variations in angular momentum represent fundamental constraints for any model of galaxy formation. We have improved the method of analysis of the alignment of galaxies in clusters. Now, the method allowed analysis both position angles of galaxy major axes and two angles describing the spatial orientation of galaxies. The distributions of analyzed angles were tested for isotropy by applying…
HST observation of the inner coma of 2060 chiron
1995
Abstract The analysis of persistent comae of very large and distant comets allows us to infer the poorly known physical properties of dust and icy grains produced beyond Jupiter. Chiron is particularly interesting because Fulle ( Astron. Astrophys. 282 , 980–988; 1994) has shown that the strong asymmetricity of its coma (West, Astron. Astrophys. 241 , 635–645 1991) allows us to infer rotational properties of Chiron's nucleus. In this paper we report the observation of the asymmetric inner coma of Chiron from the analysis of 44 images of Chiron and eight images of a standard star available from the HST archive. The images were taken during February/March 1993, when Ch iron was 9.3 AU from th…
Numerical evidence of hyperscaling violation in wetting transitions of the random-bond Ising model in d = 2 dimensions
2017
We performed extensive simulations of the random-bond Ising model confined between walls where competitive surface fields act. By properly taking the thermodynamic limit we unambiguously determined wetting transition points of the system, as extrapolation of localization-delocalization transitions of the interface between domains of different orientation driven by the respective fields. The finite-size scaling theory for wetting with short-range fields establishes that the average magnetization of the sample, with critical exponent β, is the proper order parameter for the study of wetting. While the hyperscaling relationship given by γ+2β=ν +ν requires β=1/2 (γ=4, ν =3, and ν =2), the therm…
Surface contribution to the anisotropy of magnetic nanoparticles.
2002
We calculate the contribution of the Neel surface anisotropy to the effective anisotropy of magnetic nanoparticles of spherical shape cut out of a simple cubic lattice. The effective anisotropy arises because deviations of atomic magnetizations from collinearity and thus the energy depends on the orientation of the global magnetization. The result is second order in the Neel surface anisotropy, scales with the particle volume and has cubic symmetry with preferred directions [+-1,+-1,+-1].
Spin-orbit torques in locally and globally non-centrosymmetric crystals: Antiferromagnets and ferromagnets
2016
One of the main obstacles that prevents practical applications of antiferromagnets is the difficulty of manipulating the magnetic order parameter. Recently, following the theoretical prediction [J. \v{Z}elezn\'y et al., PRL 113, 157201 (2014)], the electrical switching of magnetic moments in an antiferromagnet has been demonstrated [P. Wadley et al., Science 351, 587 (2016)]. The switching is due to the so-called spin-orbit torque, which has been extensively studied in ferromagnets. In this phenomena a non-equilibrium spin-polarization exchange coupled to the ordered local moments is induced by current, hence exerting a torque on the order parameter. Here we give a general systematic analys…
Identification of Néel Vector Orientation in Antiferromagnetic Domains Switched by Currents in NiO/Pt Thin Films
2021
Understanding the electrical manipulation of the antiferromagnetic order is a crucial aspect to enable the design of antiferromagnetic devices working at THz frequencies. Focusing on collinear insulating antiferromagnetic $\mathrm{Ni}\mathrm{O}/\mathrm{Pt}$ thin films as a materials platform, we identify the crystallographic orientation of the domains that can be switched by currents and quantify the N\'eel-vector direction changes. We demonstrate electrical switching between different T domains by current pulses, finding that the N\'eel-vector orientation in these domains is along [$\ifmmode\pm\else\textpm\fi{}5$ $\ifmmode\pm\else\textpm\fi{}5$ 19], different compared to the bulk $⟨112⟩$ d…
Orientation-dependent direct and inverse spin Hall effects in Co60Fe20B20
2019
The spin Hall effect is a key element of various spintronics applications. Here, the authors study the orientation-dependent interconversion of spin and charge information in Co${}_{60}$Fe${}_{20}$B${}_{20}$. In a nonlocal magnon transport using Y${}_{3}$Fe${}_{5}$O${}_{12}$ as a spin conduit, the spin Hall effect amplitude depends on the relative alignment between the Y${}_{3}$Fe${}_{5}$O${}_{12}$ and Co${}_{60}$Fe${}_{20}$B${}_{20}$ magnetization vectors. In order to suppress direct magnonic contributions so as to study the electronic origin of this effect, Y${}_{3}$Fe${}_{5}$O${}_{12}$ and Co${}_{60}$Fe${}_{20}$B${}_{20}$ are exchange-decoupled by a Cu interlayer.
Ideal glass transitions for hard ellipsoids
2000
For hard ellipsoids of revolution we calculate the phase diagram for the idealized glass transition. Our equations cover the glass physics in the full phase space, for all packing fractions and all aspect ratios X$_0$. With increasing aspect ratio we find the idealized glass transition to become primarily be driven by orientational degrees of freedom. For needle or plate like systems the transition is strongly influenced by a precursor of a nematic instability. We obtain three types of glass transition lines. The first one ($\phi_c^{(B)}$) corresponds to the conventional glass transition for spherical particles which is driven by the cage effect. At the second one ($\phi_c^{(B')}$) which oc…
Some aspects of the orientation of galaxies in clusters
2013
The analysis of Tully's groups of galaxies belonging to the Local Supercluster (LSC) was performed. In the 1975 Hawley and Peebles presented the method for investigations of the galaxies orientation in the large structures. In our previous papers statistical test proposed by Hawley and Peebles for investigation of this problem was analyzed in details and some improvements were suggested. On this base the new method of the analysis of galactic alignment in clusters was proposed. Using this method, God{\l}owski (2012) analyzed the orientation of galaxies inside Tully's group founding no significant deviations from isotropy both in orientation of position angles and $\delta_D$ and $\eta$ angle…
The orientations of galaxy groups and formation of the Local Supercluster
2009
We analysed the orientation of galaxy groups in the Local Supercluster (LSC). It is strongly correlated with the distribution of neighbouring groups in the scale till about 20 Mpc. The group major axis is in alignment with both the line joining the two brightest galaxies and the direction toward the centre of the LSC, i.e. Virgo cluster. These correlations suggest that two brightest galaxies were formed in filaments of matter directed towards the protosupercluster centre. Afterwards, the hierarchical clustering leads to aggregation of galaxies around these two galaxies. The groups are formed on the same or similarly oriented filaments. This picture is in agreement with the predictions of nu…