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H Akoh

Publications and source records attributed to H Akoh.

7 recordsLinked to original sources
PubMed2006

Enhanced optical magnetoelectric effect in a patterned polar ferrimagnet.

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.

Journal Article↗
PubMed2005

Optical magnetoelectric effect in a submicron patterned magnet.

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.

Journal Article↗
PubMed1990

Credit and blame among American and Japanese children: normative, cultural, and individual differences.

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.

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