Noise measurement near the transition region in YBa2Cu3O7−δ thin-film superconductor

Abstract

We have measured the noise spectrum near the transition temperature of the high-Tc superconductor YBa2Cu3O7−δ thin film which shows a rather broad transition temperature width with the onset transition temperature Tc,onset=90 K and the zero-resistance temperature Tc,zero=30 K. We observed two noise peaks, one near the onset transition temperature (81 K) and another one near the zero-resistance temperature (45 K). These two noise peaks show distinctively different dependences on the magnetic field and driving current. Furthermore, the frequency dependence of the noise spectrum at 81 K shows 1/f behavior while that of the noise spectrum at 45 K shows 1/f(1+α) behavior with α approaching 1, as the magnetic field is increased. The noise peak near the zero-resistance temperature region is believed to be due to the noise associated with the motion of free vortices.

Source-reported materials — not catalogue approval

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