Relaxation Oscillators Made of YBaCuO Thin Films

Abstract
It has been found that YBaCuO thin films exhibit hysteretic I-V characteristics in the case of high critical current densities of j C(4.2 K)>106 A/cm2. By using the hysteretic I-V characteristics, relaxation oscillators can be constructed, where YBaCuO thin films are shunted by an external inductance and a resistance. The properties of the relaxation oscillator agree well with those of an equivalent circuit model. A preliminary experiment is also made on the optical response of the oscillation frequency in order to study the possibility of the relaxation oscillator as an optical sensor.