Magnetic noise properties of YBCO/PBCO superlattices

We have measured the magnetic flux noise of two discs of YBCO/PBCO. The specimens were grown by pulsed laser ablation, had 10 alternating layers of YBCO and PBCO but with different thicknesses of PBCO. Each specimen was characterised by X-ray diffraction and a/c susceptibility measurement. We find that the noise peaks sharply at around Tc for each sample and with a noise power which is Tc dependent. We compare the results with a single layer YBCO film grown by co-evaporation.<
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