Electrical second harmonic generation by TGSe and TGS-Se in the autostabilized state

Electrical second harmonic generation and temperature autostabilized nonlinear dielectric element in ferroelectric solid solutions (Na x K1−x )VO3 and (Na x Li1−x )VO3

“…From figures 2 and 3 it is clear that when the d.c. bias voltage is zero there is still some second harmonic output. This is in agreement with the results of Abe etal (1971), Mansing and Eswar Prasad (1977) and of Chavan and Patil (1980). This zero off-set might be due to the presence of defects, giving rise to an internal bias, which in turn generates second harmonic.…”

“…where C is the capacitance of the TANDEL element, °'1 the small series resistance, ~o the sinusoidal frequency and B the material specific constant. From (1) the generated second harmonic is proportional to polarization Po (which is proportional to applied d.c. bias) and to P~ (which is proportional to the square of the applied a.c. voltage), Similar results were reported by Malek et al (1964) and Mansing and Eswar Prasad (1977) for TGS and by Chavan and Patil (1980) for TGSe and TGS-Se. The region over which the second harmonic is linear with the applied d.c. bias can be extended by increasing the a.c. voltages.…”

“…The generated second harmonic should be proportional to the square of the applied a.c. voltage according to (1). But in the present studies, as also in the work of Mansing and Eswar Prasad (1977) and of Chavan and Patil (1980), no such variation was observed perhaps due to the basic TANDEL behaviour. The TANDEL element adjusts its impedance against the variations of applied a.c. voltage, so that the product CP z in (1) remains constant which is in agreement with the theory of TANDEL given by Dvorak et al (1964).…”

“…The experimental set-up (figure 1) is similar to that used by Mansing and Eswar Prasad (1977) and Chavan and Patil (1980). We have studied voltage response of TANDEL elements of (Nax K1-x)VO3 and (Nax Lix-x)VO3 with a pure resistor of 10 ohm connected in series with them.…”

“…Mansing and Eswar Prasad (1977) studied SHG and TANDEL effects in triglycine sulphate and suggested that the zero off-set might be due to the presence of defects which in turn give rise to an internal bias. Chavan and Patil (1980) reported that the defects and dislocations in the crystal give rise to an internal bias for TGSe and TGS-Se.…”