A Possible Novel Scanning Ultrasonic Tip Microscope

Abstract

An rf-ultrasonic pulse of about 1.4 MHz has been sent into an STM tip 1 mm in diameter and 8 mm long by a piezoelectric transducer cemented to the end surface of the tip. Well-isolated ultrasonic pulse-echoes have been received by the transducer, and the conventional ultrasonic pulse superposition method has been applied to the pulse-echoes. The phase-sensitive output of the method has been found to change almost reversibly against the tip-to-surface distance in nanometer scale. The possibility of a new scanning ultrasonic tip microscope (SUTM), where the output is fed back to control the tip position instead of the current in STM, is demonstrated.