Magnetotransport in a periodic composite medium: New phenomena in a classical physics context

The magnetotransport properties of a composite conductor with a periodic microstructure have recently been studied both theoretically and numerically using a local classical continuum physics description of the transport at the microscale. Surprising new phenomena were discovered, including an induced magnetoresistance which oscillates strongly when the magnetic field is sufficiently strong and is rotated with respect to the microstructure. A surprising aspect of this phenomenon is that the effect is much stronger when the microstructure is two dimensional than when it is three dimensional. The physical reasons for this are discussed. Briefly, this is concerned with the question of whether the current distribution saturates with increasing strength of the magnetic field. In two-dimensional metal-insulator microstructures, the magnetoresistance usually does not saturate. But when it does, some components of the local current distribution must exhibit a surprising degree of uniformity over the conducting constituent.