Large Anomalous Hall effect in a silicon-based magnetic semiconductor

Magnetic semiconductors are attracting high interest because of their potential use for spintronics, a new technology which merges electronics and manipulation of conduction electron spins. (GaMn)As and (GaMn)N have recently emerged as the most popular materials for this new technology. While Curie temperatures are rising towards room temperature, these materials can only be fabricated in thin film form, are heavily defective, and are not obviously compatible with Si. We show here that it is productive to consider transition metal monosilicides as potential alternatives. In particular, we report the discovery that the bulk metallic magnets derived from doping the narrow gap insulator FeSi with Co share the very high anomalous Hall conductance of (GaMn)As, while displaying Curie temperatures as high as 53 K. Our work opens up a new arena for spintronics, involving a bulk material based only on transition metals and Si, and which we have proven to display a variety of large magnetic field effects on easily measured electrical properties.Comment: 19 pages with 5 figure

Kant

Neste texto o autor apresenta uma síntese da filosofia da religião de Kant. Ele mostra a relevância das críticas de Kant para a reflexão pós-kantiana sobre a religião. Mas ele também acentua as ambigüidades em que o pensamento de Kant se envolveu. O ponto principal é que há uma cisão entre a crítica da razão pura e a da razão prática. Isto levou a problemas teóricos que só poderiam ter sido resolvidos pelo abrandamento da reivindicação de autonomia racional. Apesar disso, a filosofia de Kant continha o núcleo para os desenvolvimentos posteriores -divergentes -na filosofia da religião