RESISTIVITY AND MAGNETORESISTANCE OF AMORPHOUS FEXGE1-X ALLOYS NEAR THE METAL-INSULATOR-TRANSITION

Electrical transport mechanisms near the metal-insulator transition are investigated in the amorphous FexGe1-x system (0.05 less-than-or-equal-to x less-than-or-equal-to 0.30) by measuring the resistivity between 100 mK and 273 K and the magnetoresistance between 100 mK and 6 K in magnetic fields up to 3.86 T. In the metallic samples, an anomalous dip in the resistivity is observed on cooling below 50 K, followed by an increase in the resistivity below about 10 K. The results of the measurements am compared to the predictions of current theories of variable-range hopping with interactions on the insulating side of the transition, and electron-electron interactions and weak localization on the metallic side of the transition.