Second harmonic generation and TANDEL effect studies on ferroelectric triglycine selenate and triglycine sulphate-Selenate crystals near the Curie temperature indicate that the generated second harmonic is linear for low biasing fields with a zero off-set, while it decreases sharply at higher biasing fields. In the autostabilized state, the TANDEL elements adjust their impedance against the variation of a.c. field. The experiments on annealed crystals establish that the zero offset is due to the internal bias that owes its origin to the defect structure.

tandel effect and second harmonic generation studies on ferroelectric solid solutions (lead, strontium) titanate and (lead, calcium) titanate were carried out near the Curie temperature. The generated second harmonics are linear for low biasing fields with a zero off-set, while they decrease sharply at higher biasing fields. In the autostabilized state, thetandel elements adjust their impedance against the variations of a.c. field. Zero off-set might have been caused due to the presence of delects giving rise to an internal bias which in turn generates second harmonic.

The temperature autostabilizing nonlinear dielectric element (TANDEL) effect and second harmonic generation have been studied in the ferroelectric solid solutions of (Pb_x-Ba_1−x)TiO₃ and (Pb_x-Sr_1−x)TiO₃ near the Curie temperature used as TANDEL. The generated second harmonics are linear for low d.c. biasing fields with zero off-set while they decrease sharply at higher d.c. biasing fields. The results show that these solid solutions might be used as TANDEL elements.

The thermoelectric power of ferroelectric sodium vanadate doped with different concentrations of lanthanum oxide has been measured in the temperature range covering their transition temperatures. It has been observed that the thermoelectric power increases with temperature, attains maximum value and with further increase in the temperature decreases to zero, indicating Curie temperature of the respective samples; however, it changes the sign for higher temperature. The thermoelectric power of sodium vanadate increases to maximum with increase in doping concentration of lanthanum oxide from 0.025 to 0.1 mol%; however, it decreases for higher concentrations. Pure as well as lanthanum oxide doped sodium vanadate samples showp-type behaviour in the ferroelectric region andn-type behaviour in the paraelectric region.