TIME-RESOLVED OBSERVATION OF THERMAL OSCILLATIONS BY TRANSMISSION ELECTRON-MICROSCOPY

Time-dependent acoustic oscillations driven by stochastic thermal forc e have been observed by means of transmission electron microscopy. An electron-beam current passing in the vicinity of the edge of the vibra ting sample, and thereby modulated, was led through an aperture at the image plane and measured with the electron counting technique as the power spectral density function, allowing the resonant frequency and t he Q factor to be found. This enables estimation of the Young's modulu s and the internal friction. The method can be extended to the investi gation of the elastic properties of nanoscaled samples. (C) 1997 Ameri can Institute of Physics.