Magnetoresistive switch effect in metal/semiconductor hybrid granular films--extra huge magnetoresistance effect at room temperature

A granular film consisting of nanoscale metal clusters that are grown on a GaAs substrate by molecular-beam epitaxy exhibits magnetic-field-sensitive current-voltage characteristics at room temperature. When a constant voltage, above the threshold value, is applied to the film, a steep current-increase appears. The abrupt increase disappears on applying magnetic fields, which we term magnetoresistive switch. The switch yields a huge positive magnetoresistance effect, 320 000% at 2000 Oe