Search results for "C.M.M."
showing 10 items of 1066 documents
Effect of Prime and Target Repetition on Lexical Decision Time
1992
On a prime-target lexical decision task we manipulated the relatedness between prime and target (semantically related or unrelated), the number of repetitions (from 1 to 5), the type of the repeated stimulus (only the prime, only the target, or both), and the stimulus onset asynchrony (within a range of automatic activation from 60 to 400 msec.) to find whether semantic and repetition priming are additive (or interact), and whether there is episodic priming in an automatic, nonconscious way. Analysis showed repetition and semantic priming were additive rather than interactive. No episodic automatic priming was found. Results are discussed in terms of the predictions made from the main theo…
Modelling the Effects of Internal Textures on Symmetry Detection Using Fuzzy Operators
2009
Symmetry is a crucial dimension which aids the visual system, human as well as artificial, to organize its environment and to recognize forms and objects. In humans, detection of symmetry, especially bilateral and rotational, is considered to be a primary factor for discovering and interacting with the surrounding environment. Rotational symmetry detecting can be affected by less-known factors, such as the stimulus internal texture. This paper explores how fuzzy operators can be usefully employed in modeling the effects of the internal texture on symmetry detection. To this aim, we selected two symmetry detection algorithms, based on different computational models, and compared their output…
Integrative Pedagogy in Practicum
2011
The chapter introduces a model of integrative pedagogy in teaching practicum within a Finnish context. The aim of this action research project is to integrate educational theory and practice in teaching practicum with a view to promote student teachers professional autonomy. In the Integrative Pedagogy Model, theoretical knowledge, practical skills and self-regulation (reflective and metacognitive skills) are merged. The empirical part of the chapter is based on the content analysis of the experiences of students and their supervising teachers. The results show that an exceptional sense of community is being achieved in this kind of teaching practicum.
Half-metallic ferromagnetism with high magnetic moment and high Curie temperature in Co$_2$FeSi
2006
Co$_2$FeSi crystallizes in the ordered L2$_1$ structure as proved by X-ray diffraction and M\"o\ss bauer spectroscopy. The magnetic moment of Co$_2$FeSi was measured to be about $6\mu_B$ at 5K. Magnetic circular dichroism spectra excited by soft X-rays (XMCD) were taken to determine the element specific magnetic moments of Co and Fe. The Curie temperature was measured with different methods to be ($1100\pm20$)K. Co$_2$FeSi was found to be the Heusler compound as well as the half-metallic ferromagnet with the highest magnetic moment and Curie temperature.
Electronic properties of Co2FeSi investigated by X-ray magnetic linear dichroism
2014
We present experimental XMLD spectra measured on epitaxial (001)-oriented thin Co$_{2}$FeSi films, which are rich in features and depend sensitively on the degree of atomic order and interdiffusion from capping layers. Al- and Cr-capped films with different degrees of atomic order were prepared by DC magnetron sputtering by varying the deposition temperatures. The local structural properties of the film samples were additionally investigated by nuclear magnetic resonance (NMR) measurements. The XMLD spectra of the different samples show clear and uniform trends at the $L_{3,2}$ edges. The Al-capped samples show similar behavior as previous measured XMLD spectra of Co$_2$FeSi$_{0.6}$Al$_{0.4…
Seebeck coefficients of half-metallic ferromagnets
2009
In this report the Co2 based Heusler compounds are discussed as potential materials for spin voltage generation. The compounds were synthesized by arcmelting and consequent annealing. Band structure calculations were performed and revealed the compounds to be half-metallic ferromagnets. Magnetometry was performed on the samples and the Curie temperatures and the magnetic moments were determined. The Seebeck coefficients were measured from low to ambient temperatures for all compounds. For selected compounds high temperature measurements up to 900 K were performed.
Thermal generation of spin current in epitaxial CoFe2O4 thin films
2016
The longitudinal spin Seebeck effect (LSSE) has been investigated in high-quality epitaxial CoFe2O4 (CFO) thin films. The thermally excited spin currents in the CFO films are electrically detected in adjacent Pt layers due to the inverse spin Hall effect (ISHE). The LSSE signal exhibits a linear increase with increasing temperature gradient, yielding a LSSE coefficient of ~100 nV/K at room temperature. The temperature dependence of the LSSE is investigated from room temperature down to 30 K, showing a significant reduction at low temperatures, revealing that the total amount of thermally generated magnons decreases. Furthermore, we demonstrate that the spin Seebeck effect is an effective to…
Slater-Pauling Rule and Curie-Temperature of Co$_2$-based Heusler compounds
2005
A concept is presented serving to guide in the search for new materials with high spin polarization. It is shown that the magnetic moment of half-metallic ferromagnets can be calculated from the generalized Slater-Pauling rule. Further, it was found empirically that the Curie temperature of Co$_2$ based Heusler compounds can be estimated from a seemingly linear dependence on the magnetic moment. As a successful application of these simple rules, it was found that Co$_2$FeSi is, actually, the half-metallic ferromagnet exhibiting the highest magnetic moment and the highest Curie temperature measured for a Heusler compound.
Nonmagnetic and magnetic thiolate-protected Au25superatoms on Cu(111), Ag(111), and Au(111) surfaces
2012
Geometry, electronic structure, and magnetic properties of methylthiolate-stabilized Au$_{25}$L$_{18}$ and MnAu$_{24}$L$_{18}$ (L = SCH$_3$) clusters adsorbed on noble-metal (111) surfaces have been investigated by using spin-polarized density functional theory computations. The interaction between the cluster and the surface is found to be mediated by charge transfer mainly from or into the ligand monolayer. The electronic properties of the 13-atom metal core remain in all cases rather undisturbed as compared to the isolated clusters in gas phase. The Au$_{25}$L$_{18}$ cluster retains a clear HOMO - LUMO energy gap in the range of 0.7 eV to 1.0 eV depending on the surface. The ligand layer…
Microscopic origin of magnetic anisotropy in martensitic Ni2MnGa
2011
The microscopic origin of magnetic anisotropy in the shape memory alloy Ni${}_{2}$MnGa is investigated by means of x-ray magnetic circular dichroism in transmission mode. Field- and angle-dependent dichroism spectra of epitaxial Ni${}_{2}$MnGa(101)/MgO(001) films reveal pronounced differences for magnetization aligned parallel and perpendicular to the film plane. These differences are related to an anisotropy of the orbital magnetic moment in agreement with the observed out-of-plane magnetocrystalline anisotropy. The spectral variation of the x-ray absorption originates from changes in the spin-projected density of states when the magnetization vector is rotated from the easy to the hard ma…