EVOLUTION OF A METALLIC AND MAGNETIC STATE IN (Fe, Mn)Si AND Fe(Si, Ge)

An analysis of the pressure-dependent resistivity of FexMn1-xSi(1 less than or equal to x less than or equal to 0.82) and FeSixGe1-x (1 less than or equal to x less than or equal to 0.6) alloys in terms of a Kondo insulator description revealed a pressure-induced opening of the narrow gap. A negative magnetoresistance is observed for Fe-rich alloys of FexMn1-xSi at elevated temperatures.