The Non-Linear Electro-Ultrasonic Spectroscopy

The ultrasonic signal is familiarly used in non-destructive spectroscopy. The paper presents the new method of the non-destructive testing procedure of conductive materials. The non-linear electro-ultrasonic spectroscopy is new method which has higher sensitivity and range of using than common ultrasonic testing method which has many problems. We are applying two signals: (i) ultrasonic signal with frequency f_U and (ii) harmonic AC electric signal of frequency f_E. The ultrasonic phonons modulate the transport of electrons through the structure and in the vicinity of defects and un-homogeneities the intermodulation signal is created. The frequency f_m of the intermodulation signal is given by the superposition or subtraction of exciting frequencies f_U and f_E.The main advantage of this method is the detection of electrical signal with frequency f_m which is different from frequencies of excitation signals. We are measuring the signal with frequency f_m=f_U-f_E.