ANOMALOUS ELECTRICAL RESISTIVE BEHAVIOR OF AL-O-PB SPUTTERED ALLOYS

Application of the sputtering technique to (Al-O)//xPb//1//0//0// minus //x alloys containing an immiscible lead element has been found to result in the formation of a duplex material consisting of fcc lead particles dispersed in an amorphous Al//xO//y oxide matrix. The particle size and interparticle distance of the lead phase were about 10 to 50 nm and 10 to 40 nm, respectively. The Al-O-Pb alloys have been found to exhibit an extremely high electrical resistivity, as well as a large positive temperature-dependent resistivity. The peculiar resistivity behavior was interpreted by assuming the mechanism that only the lead phase embedded in Al//xO//y matrix contributes to electrical conductivity and the mobility of lead electrons is greatly reduced in the intervening oxide region among lead phases. It has thus been demonstrated that the composite material exhibiting peculiar characteristics, which cannot be achieved in metallic composite materials, is obtained by simultaneously sputtering oxide and an insoluble metallic element.