Detection of irradiated microwaves in stripe-shaped intrinsic Josephson junctions

이후종

Akinobu Irie, Masahiro Iwama, Gin-ichiro Oya

We have been investigated the current - voltage characteristics of naturally stacked intrinsic Josephson junctions in mesa-shaped single crystals, having dimensions in the ab plane larger than the Josephson penetration depth, without and with microwave irradiations. In the absence of microwave irradiation, a gaplike feature and multiple resistive branches that imply SIS series junctions were observed in the current - voltage characteristic. Under appropriate conditions of microwave irradiation, we successfully observed striking microwave-induced subharmonic steps, caused by the phase-locked oscillation of a coupled multifluxon, with nearly equal voltage separations on the I - V characteristics of a mesa in the cavity resonant mode.

A. L. Gudkov, В. А. Ильин, V. N. Laptev +2 more

Takashi Tachiki, Takashi Uchida, Yoshizumi Yasuoka

Microwave-induced steps were observed in I-V characteristics of intrinsic Josephson junctions fabricated on an overdoped BSCCO single crystal with a weak magnetic field parallel to the c-axis. Voltage intervals between the steps under the irradiation of 12.2, 13.2 and 13.9 GHz microwaves were independent of the microwave power and proportional to the frequency. From the measurement of voltage intervals, it was found that all the junctions in the fabricated junction stack simultaneously produced Shapiro steps, assuming that the steps are Shapiro steps.

I. I. Yurchenko, V. S. Kartavtsev, V. I. Matveev +1 more

Yu. M. Shukrinov, Michael Mans, Jens Scherbel +1 more

The current–voltage characteristics of a micrometre bridge of intrinsic Josephson junctions under microwave irradiation are studied. The collective switching of the group of four junctions splits up as the AC signal amplitude is gradually increased. The switching current of the remaining group of junctions is increased with increasing radiation power. We consider that microwave irradiation injects an additional quasiparticle current into the Josephson junction array. We use ideas of breakdown of quasineutrality and quasiparticle charge imbalance in the superconducting layers and explain the experimental results by the competition between the 'current effect' and the effect of suppression of the switching current by irradiation.