18 research outputs found
Finite-size effects on the magnetoelectric response of field-driven ferroelectric/ferromagnetic chains
We study theoretically the coupled multiferroic dynamics of one-dimensional
ferroelectric/ferromagnet chains driven by harmonic magnetic and electric
fields as a function of the chain length. A linear magnetoelectric coupling is
dominated by the spin-polarized screening charge at the interface. We performed
Monte-Carlo simulations and calculations based on the coupled
Landau-Lifshitz-Gilbert and Landau-Khalatnikov equations showing that the net
magnetization and the total polarization of thin heterostructures, i.e. with up
to ten ferroelectric and ferromagnetic sites counted from the interface, can be
completely reversed by external electric and magnetic fields, respectively.
However, for larger system solely a certain magnetoelectrical control can be
achieved.Comment: J. Phys.: Conf. Series. (2011) (to be published
Piezoelectric control of the magnetic anisotropy via interface strain coupling in a composite multiferroic structure
We investigate theoretically the magnetic dynamics in a
ferroelectric/ferromagnetic heterostructure coupled via strain-mediated
magnetoelectric interaction. We predict an electric field-induced magnetic
switching in the plane perpendicular to the magneto-crystalline easy axis, and
trace this effect back to the piezoelectric control of the magnetoelastic
coupling. We also investigate the magnetic remanence and the electric
coercivity
Social Anxiety Modulates Subliminal Affective Priming
BACKGROUND: It is well established that there is anxiety-related variation between observers in the very earliest, pre-attentive stage of visual processing of images such as emotionally expressive faces, often leading to enhanced attention to threat in a variety of disorders and traits. Whether there is also variation in early-stage affective (i.e. valenced) responses resulting from such images, however, is not yet known. The present study used the subliminal affective priming paradigm to investigate whether people varying in trait social anxiety also differ in their affective responses to very briefly presented, emotionally expressive face images. METHODOLOGY/PRINCIPAL FINDINGS: Participants (n = 67) completed a subliminal affective priming task, in which briefly presented and smiling, neutral and angry faces were shown for 10 ms durations (below objective and subjective thresholds for visual discrimination), and immediately followed by a randomly selected Chinese character mask (2000 ms). Ratings of participants' liking for each Chinese character indicated the degree of valenced affective response made to the unseen emotive images. Participants' ratings of their liking for the Chinese characters were significantly influenced by the type of face image preceding them, with smiling faces generating more positive ratings than neutral and angry ones (F(2,128) = 3.107, p<0.05). Self-reported social anxiety was positively correlated with ratings of smiling relative to neutral-face primed characters (Pearson's r = .323, p<0.01). Individual variation in self-reported mood awareness was not associated with ratings. CONCLUSIONS: Trait social anxiety is associated with individual variation in affective responding, even in response to the earliest, pre-attentive stage of visual image processing. However, the fact that these priming effects are limited to smiling and not angry (i.e. threatening) images leads us to propose that the pre-attentive processes involved in generating the subliminal affective priming effect may be different from those that generate attentional biases in anxious individuals
Influence of dipole-dipole interactions on the angular dependence of ferromagnetic resonance spectra in arrays of Fe/Fe
We present a detailed theoretical study of the role of long-range dipole-dipole
interactions on the angular dependence of ferromagnetic resonance spectra in a
two-dimensional array of nanocubes. Variations of polar (φ) and azimuthal
(θ) angles
are studied numerically and analytically to illustrate the effect of the
magnetocrystalline properties and the dipole-dipole interactions, forming complex
resonance bands. In addition, we show that when the static magnetic field lies in the
arrays’ plane under the angle of 129° with the edge of the array or when its tilted around
15° to the plane’s normal,
the spectra of absorption transform into a plateau spanning from 0.1 T to 0.4 T, which is
prominent enough for experimental observation