2001 Volume 42 Issue 8 Pages 1705-1709
A small solenoid coil was equipped with a scanning tunneling electron microscope (STM) which has an iron needle core tip as the probe. Mutual inductance of the coil with a thin gold film on a mica plate was investigated in order to profile electrical conductivity. It is important to maintain a small gap between the tip apex and the sample surface. The gap is related to the distribution of electron scattering by induced current. The conductivity mapping was carried out on a large terrace. If the tip is over the step edge, the output signal from the probe coil becomes unstable. Atomically smooth surface of the specimen was in need for the electrical conductivity mapping. The electrical conductivity on the terrace was almost constant. The mutual inductance values with the gold film at various temperatures were investigated by cooling it below 250 K . The mutual inductance is inversely proportional to the temperature to the one-third power, T1⁄3. The relationship between the mutual inductance and the temperature was explained by the electromagnetic theory.
