High-frequency harmonics generation by Bi2Sr2Ca2Cu3O y ceramic carrying alternating transport current

We have detected the nonlinear magnetic flux generated by a superconducting slab in the presence of an alternating transport current alone, and with no external fields around during the detection. The temperature dependence of induced flux is found to be analogous in its main features to the nonlinear susceptibility: (1) only odd harmonics exist, (2) the third-harmonic signal is bell shaped with temperature, and (3) it is quite similar to the temperature dependence of the lossy component of the susceptibility at the fundamental frequency. Furthermore, two regimes, intra- and intergranular supercurrent contributions, can also be distinguished. These observations suggest a new method for the determination of critical current and its temperature dependence. The observed effective higher harmonics generation may be used in developing novel nonlinear superconducting components such as new types of frequency multipliers and multifrequency generators.