ABSTRACT
A surface decontamination system for application in surface sensitive magnetic imaging tools, such as a spin-polarized scanning electron microscope, is described. Adsorbed contaminant is chemically decomposed with the use of active oxygen in a compact vacuum chamber mounted in a microscope. The present method is especially suitable for fragile magnetic surfaces of complex oxide materials to which the conventional physical etching widely used for magnetic metals could cause serious structural damage. We have succeeded in detecting magnetic signals from a decontaminated oxide surface and visualizing domain images with sufficient magnetic contrast to analyze detailed domain structures.
ABSTRACT
Nonreciprocal directional dichroism, termed the optical magnetoelectric (OME) effect, has been observed in patterned superlattice (SL) composed of perovskite oxides, LaMnO3, SrMnO3, and LaAlO3. Such a tricolor SL with ferromagnetic interfaces is expected to artificially break both space-inversion and time-reversal symmetries and hence to show the OME effect. The Bragg diffraction from the grating structure with a period of 4 microm fabricated on the SL was employed to sensitively detect the OME effect, yielding the relative change of the diffracted light intensity (~0.2%-0.5%) upon a reversal of either the in-plane magnetization or the propagation vector of the diffracted light.
ABSTRACT
A simple method to dramatically enhance the optical magnetoelectric (ME) effect, i.e., nonreciprocal directional birefringence, is proposed and demonstrated for a polar ferrimagnet GaFeO3 as a typical example. We patterned a simple grating with a period of 4 microm on a surface of GaFeO3 crystal and used the diffracted light as a probe. The optical ME modulation signal for the Bragg spot of the order n=1 becomes gigantic in the photon energy 1-4 eV and reaches 1-2% of the bare diffracted light intensity in a magnetic field of 500 Oe. This is amplified by more than 3 orders of magnitude compared to that for the reflection of bulk GaFeO3. Fabricating a photonic crystal will make it possible to lead the way for the practical use of the optical ME effect.
ABSTRACT
The optical magnetoelectric effect, which is a nonreciprocal directional dichroic response, has been demonstrated in a submicron patterned magnet by monitoring the diffracted visible or near-infrared light intensity. An artificial magnetic superstructure is composed of chevron shaped ">" islands made of the ferromagnetic permalloy Ni(80)Fe(20) with a pitch of 1 microm on silicon substrate, in which both space inversion and time reversal symmetry are broken simultaneously. On the basis of the light-polarization angle and magnetic field H dependence, and also comparing the results with the those of the submicron square patterns, we show that the optical magnetoelectric effect emerges as the finite change (approximately 10(-3) at room temperature in H of 500 Oe) of the diffracted intensity.
ABSTRACT
Japanese and American 5th graders (N = 593 children, 198 American and 395 Japanese) assigned credit and blame to good and bad classroom deeds and performances. Theoretically, a morality of aspiration involves assigning more credit for a good deed than blame for a corresponding bad deed; a morality of duty involves assigning more blame than credit. In both countries academic achievement norms were most consistent with aspiration, moral norms were judged as duties, and procedural norms were intermediate. Japanese children's responses were more consistent with aspiration than those of Americans. Analyses also explored cultural versus individual differences in sanctioning. The conclusion addresses the relevance of the concept of aspiration to the study of achievement and other norms.
