MAGNETORESISTANCE OSCILLATION IN A 2-DIMENSIONAL ELECTRON-GAS UNDER PERIODIC MODULATION OF ELECTRIC AND MAGNETIC-FIELDS

We have studied oscillatory magnetoresistance (Weiss oscillation) in a two-dimensional electron gas (2DEG) subjected to a one-dimensional pe riodic modulation of both electric and magnetic fields. The relative a mplitude of the two types of modulation can be controlled by applying a bias voltage to a gate consisting of a periodic array of ferromagnet ic metal stripes. Allowing the magnetic modulation to dominate by appl ying +500 mV to the gate, we succeeded in observing magnetic Weiss osc illation which is characterized by peak/valley inversion in the magnet oresistance oscillation and not with regard to its well-known electric counterpart. The oscillation curve shows continuous phase shift with smaller gate biases, until it reaches the peak/valley location of elec tric Weiss oscillation at about -250 mV.