Magnetosensitive conductivity of aluminum and the advantage of Corbino geometry

Abstract

Aluminum being uncompensated metal has a small magnetoresistance and this property is usually not used in magnetosensitive devices. On other hand in cylinder-like sample with current flow along the radius (Corbino geometry) the magnetoconductance is extremely small. Here the results of study of this phenomenon in A1 disk-like samples are presented. The material had residual resistance ratio 10000, an external magnetic field was up to 8T, the current flow through the sample reached 1000A, the temperature of measurements was 4.2K. The magnitude of magnetoconductance and the value of the own magnetic field due to Hall current have been determined during the study. The magnetoconductance effect reached of 5000 and the value of the own magnetic field was up to 50% of applied magnetic field. Analysis of obtained data indicates that there are possibilities of using of these phenomena in cryogenic systems of control of electrical circuits where nonlinear resistance and inductance changing parametrically by the current, its direction and an external magnetic field are required. For nonstationary transition processes the analysis is given with account of high skin effect and the characteristic times and sizes are estimated. It is necessary to note that the advantages of high pure aluminum used in such manner may be utilized most fully because in massive conductors the ponderomotive forces are not too critical as m the thin bus-bar wires. The work is supported by the National Science Foundation of Belarus through Grant No F40-249.